The Best Climate Science You’ve Never Heard Of

In an event co-sponsored with Scientific American, climate scientist Michael Mann and Saleemul Huq, director of the ICCCAD in Bangladesh, brief journalists on some surprisingly hopeful developments.

Past event:

On February 17, CCNow held a joint press briefing with Scientific American on a little-known scientific development that carries paradigm-shifting implications for how people think and feel about the climate crisis and how governments and societies respond to it.

Most journalists have long echoed what we thought was the scientific consensus: Even if greenhouse gas emissions stop, global temperatures will keep rising for 30 to 40 more years, mainly because of carbon dioxide’s long lifetime in the atmosphere. But in fact the latest science doesn’t say that. The lag time for temperature rise would actually be as little as 3 to 5 years, as was noted in the latest IPCC report last August and explained in a Scientific American article last October.

With the next IPCC report scheduled for release on February 28 this webinar will help journalists get up to speed on this and other key aspects of the latest science. Note: The IPCC has extended its deadline to Feb 22 to register for an embargoed version of the Working Group II report assessing climate change impacts, adaptation and vulnerability.


  • Dr. Michael E. Mann is a professor of Atmospheric Science at Penn State and the director of the Penn State Earth System Science Center. His most recent book is, “The New Climate War.”
  • Saleemul Huq is the director of the International Centre for Climate Change and Development in Dhaka. He trained diplomats from the global South who helped insert the 1.5 degrees Celsius goal in the Paris Agreement.

Mark Hertsgaard, CCNow’s executive director and environment correspondent at The Nation, and Scientific American’s editor in chief, Laura Helmuth, served as co-moderators.

Post-Press Briefing Follow-up Explanation

As noted in the press briefing, what CCNow has dubbed “the best climate science you’ve never heard of” was included but buried in the IPCC’s Sixth Assessment Report, Working Group 1, issued last August. Indeed, this science first emerged in the IPCC’s landmark Global Warming of 1.5 Degrees C report, released in October 2018, where it formed the basis for the concept of a “carbon budget” and the related finding that global emissions must fall by 45 percent by 2030 to limit temperature rise to 1.5 C. The most relevant passage in that report is here. See in particular Figure 1.5 and the accompanying discussion, which we’ve included below.

The phrasing employed by the IPCC scientists is, unfortunately, not easy for non-scientists to decipher, but the following is a lay person’s guide. The key graph is the bottom of the two graphs in Figure 1.5, and the key sentence is the fourth sentence in the box of text to the right of that graph. That sentence reads: “Temperatures continue to increase slightly after the elimination of CO2 emissions (blue line) in response to constant non-CO2 forcing.” A more reader friendly way to phrase this would be—we’ve added emphasis and extra wording here with italics–“Temperatures continue to increase only slightly after the elimination of CO2 emissions (blue line)…” Here, “only slightly” refers to the 3 to 5 years of additional warming that Michael Mann cited, while “elimination” refers to the hypothetical case of humanity halting all greenhouse gas emissions overnight.

You can visualize this potential halt in temperature rise by looking at the solid blue line in the bottom of the two graphs, which proceeds in an almost perfectly straight line from left to right, depicting how temperatures would remain virtually flat out to the year 2100. Be careful to follow the solid blue line and not the dotted blue line or the dashed blue line, which depict radically different scenarios.

Make sense? We hope so. Like we said yesterday, this finding was buried by IPCC scientists who didn’t realize they were burying it—no wonder the rest of us don’t know about it! Please get in touch with any further questions.

Figure 1.5: Warming commitment from past emissions of greenhouse gases and aerosols 

Source: IPCC Special Report: Global Warming of 1.5 ºC

Explanation of Figure 1.5 from the IPCC Report

“Radiative forcing (top) and global mean surface temperature change (bottom) for scenarios with different combinations of greenhouse gas and aerosol precursor emissions reduced to zero in 2020. Variables were calculated using a simple climate–carbon cycle model (Millar et al., 2017a) with a simple representation of atmospheric chemistry (Smith et al., 2018). The bars on the right-hand side indicate the median warming in 2100 and 5–95% uncertainty ranges (also indicated by the plume around the yellow line) taking into account one estimate of uncertainty in climate response, effective radiative forcing and carbon cycle sensitivity, and constraining simple model parameters with response ranges from AR5 combined with historical climate observations (Smith et al., 2018). Temperatures continue to increase slightly after elimination of CO2 emissions (blue line) in response to constant non-CO2 forcing. The dashed blue line extrapolates one estimate of the current rate of warming, while dotted blue lines show a case where CO2 emissions are reduced linearly to zero assuming constant non-CO2 forcing after 2020. Under these highly idealized assumptions, the time to stabilize temperatures at 1.5°C is approximately double the time remaining to reach 1.5°C at the current warming rate.”



Mark Hertsgaard: Hello, and welcome to this special press briefing from Covering Climate Now. I’m Mark Hertsgaard, I’m the executive director of Covering Climate Now and also the environment correspondent for The Nation Magazine. Joining me today as the co-moderator is my esteemed colleague, Laura Helmuth. She’s the editor in chief of Scientific American, which is co-sponsoring this briefing on the best climate science you’ve never heard of. Covering Climate Now is a nonprofit, nonpartisan collaboration of more than 400 news outlets around the world with a combined audience of roughly two billion people. We’re organized by journalists for journalists to help all of us do the best job we can on the defining story of our time. We help newsrooms everywhere. If you want to join us or just to access our background resources or sign up for our weekly newsletter, go to our website, We are also accepting entries now for the second annual Covering Climate Now climate journalism awards.

Mark Hertsgaard: Send us your best work. The entry stops on March 1st so you’ve got about two weeks to get it in. Again, go to the website and you’ll see how you can do that. But all beats, all countries, all journalists are invited. Covering Climate Now and Scientific American are thrilled today to have two of the world’s most distinguished climate scientists joining us for this conversation. We scheduled this session to help all journalists get up to speed before the next IPCC report. That’s the Sixth Assessment Working Group II that is due to be released on February 28, as you probably know, and then Working Group III report comes sometime in March. So we titled today’s session, the best climate science you’ve never heard of, even though the science in question was included in the Working Group IPCC report last August. It was in there, but it was buried.

Mark Hertsgaard: So virtually no one outside of the climate science community seems to know about this, unless you read Scientific American’s article on this, which was published just a few days before last November’s COP26 climate summit in Glasgow. And you’ll find a link to that in the chat here. So the gist of this largely unknown science, and obviously we’ll dig into the details in the course of this hour, but the gist is that contrary to long held assumptions, large amounts of temperature rise are not necessarily locked into the Earth’s climate system. As soon as emissions are cut to zero, temperature rise can stop within as little as three years. Three years, not the 30 to 40 years that I for one have been reporting for a long time and that most of us as journalists thought was the scientific consensus. So the upshot of this revised science is that humanity can still limit temperature rise to the 1.5 degree Celsius target, but only if we take strong action starting now.

Mark Hertsgaard: So before we get into all that, a few last housekeeping items. We’ll hear from our panelists during the first half hour, then your questions and answers during the second. You’re welcome to tweet throughout the hour using @coveringclimate and the #CCnow, and at the end, we’ll invite you to do a very quick survey, just less than two minutes really on what other topics you’d like us to cover in the talking shops and press briefings still to come. Now, I hope you will all join me in giving a very warm virtual welcome to our guest today, starting again with my esteemed co-moderator Laura Helmuth. She’s the editor in chief of Scientific American. And in the past, she’s been an editor for the Washington Post and for magazines, including National Geographic, Slate, Smithsonian, and Science. That’s Laura Helmuth.

Mark Hertsgaard: And Saleemul Huq. He’s the director of the International Centre for Climate Change and Development in Dhaka, Bangladesh, and that’s where he trained diplomats from the global south who helped insert the 1.5 degrees target into the Paris Agreement in 2015. And finally, Michael Mann. He’s the distinguished professor of atmospheric science and the director of the Earth System Science Center at Penn State University. His numerous include most recently, “The New Climate War: The Fight to Take Back Our Planet.” Covering Climate Now is so proud and grateful to have all of you with us here today. Thank you again for making the time. And now, I’ll turn it over to Laura and Michael Mann.

Laura Helmuth: Great. Thank you so much. Thank you to today’s speakers, thanks to Covering Climate Now for bringing us all together, and thank you to all of you in the audience for the work you do covering climate. It is a challenging and important and urgent and endless beat. It’s a lot of responsibility and we’re just all trying to get it right and to help one another elevate our coverage, get more attention to help the world understand what’s really happening. So we hope this conversation will be useful. And I think we want to dive right in, start with the premise, the whole framing of this meeting that Mark laid out, which is that a lot of us have had the impression that a certain amount of temperature rise is just unavoidable, perhaps 30 to 40 years no matter what we do right now based on the greenhouse gasses that are already in the atmosphere. But the latest science or the emerging science, the science that’s really gotten much more clear recently is that’s not the case and that temperature could stop rising in as little as three years.

Laura Helmuth: And so Mike, could you start us out, kind of explain, why do we think this? Where did the science come from? How do we know that things could turn around so quickly?

Michael Mann: Yeah. And thanks, Laura. Thanks, Mark, and everybody else for helping make for this conversation here today. I’ll confide something in you all. I didn’t really appreciate this aspect of the science until about five years ago. And it goes back more than a decade. The body of work that leads to this sort of revised understanding really does go back more than a decade yet, but it didn’t even fully penetrate into sort of the scientific community until more recently. And it has to do with, there is a notion that has been out there for a while, the notion of a carbon budget. This idea that there is some slug of carbon that we can still burn and keep temperatures below some level, be it one and a half degrees Celsius, three degrees Fahrenheit roughly, or two degrees Celsius. And so the reason that that concept makes sense, the reason that we can say there’s a certain amount of cumulative carbon that we can burn and keep surface temperatures below some level is because of this science.

Michael Mann: The concept of a carbon budget only makes sense because once you stop burning carbon, surface temperatures stabilize. That means that the surface temperature that you end up with really is a function of the cumulative carbon emissions up to that point in time. And so here is sort of why this understanding has… And so even though it’s implicit in much of what the climate community has been talking about in recent years, the concept of carbon budgets and stabilization of warming below these critical levels, we haven’t really done a good job on unpacking the science behind that. Why does that work? And the reason it works is that we aren’t committed to addition and old decades of warming as we used to think we were. Now in the old days, we would run our climate models with carbon dioxide as sort of a control knob. It’s just something that you dial up and you can dial it up, you can dial it down in the model.

Michael Mann: And so you’re fixing the concentration of carbon dioxide. And when you increase the carbon dioxide level, the climate slowly equilibrates to that higher level. And the reason that the equilibration process is slow is there’s what we call sort of the climate commitment, which is oceans store a huge amount of heat and they’re very sluggish. So they continue to warm up even after you stop increasing the carbon dioxide concentration. So if you increase carbon dioxide levels to, say double pre-industrial levels, and then you stop increasing them, what you’ll see is that the planet will warm for several more decades as it approaches the new equilibrium. Now we call that the climate commitment. There is this additional warming, we call it committed warming, that is in the pipeline. If that’s all that was going on, then we would be committed to additional decades of warming. But it turns out, you’ve got at this curve going like that, but there’s another curve going in the opposite direction.

Michael Mann: And that has to do with the fact that carbon dioxide levels actually start coming down once you stop emitting carbon into the atmosphere. And that’s because natural sinks, particularly the ocean, continue to take carbon out of the atmosphere. And we call it the carbon commitment. These two things are equal and opposite. One goes like that, the other goes like that. And if you add them together, they offset each other, you get a flat line. And so what that tells us is actually, if you stop emitting carbon into the atmosphere, surface temperatures stabilize very quickly within a few years. Now there’s some caveats here, that surface temperature. But remember that the oceans are continuing to absorb heat, that heat is continuing to penetrate down into the oceans, that ocean warming is continuing to destabilize ice shelves, like the ice shelves off Antarctica. So some impacts will continue to get worse and sea level rise is one of them. There was just a report yesterday. Some of you may have seen this.

Michael Mann: The NOAA report on sea level rise that tells us that we’ve got at least a foot now off the sea level rise along the East Coast of the US. We’re going to get another foot no matter what we do. That’s baked in. We can prevent that foot from turning into meters by keeping carbon emissions, again, below those critical levels to limit warming below one and a half Celsius. So there you have it. It’s taken a while for the scientific community itself to really come to an understanding of this new paradigm. And it’s been an even slower process to translate that for public consumption.

Laura Helmuth: Great. Thank you. So there’s some questions in the comments about, you’ve talked about carbon dioxide, but what about methane? Do these projections account for the effects of methane?

Michael Mann: Yeah. There’s the good news and the bad news about methane. The good news about methane is that it’s a much shorter resonance time in the atmosphere. So these dynamics I’m talking about don’t really apply to methane. The methane that we put into the atmosphere is only warming the planet for a matter of decades rather than centuries or a millennia. And so what that means is that if we bring methane emissions to zero, that effect dissipates within decades. It’s not locked in like the effect of carbon dioxide. And so when you look at this in detail, you see it isn’t just the carbon dioxide story, there’s methane, there are sulfate aerosols. The pollution generated from coal burning has actually offset some global warming. These reflective particles, we call aerosols. They’re not like a spray can, but they’re these little particles that reflect sunlight. And so pollution associated with coal burning, for example, has offset some of global warming.

Michael Mann: We call that aerosol masking and that masking will dissipate pretty quickly. When we stop burning fossil fuels, we also stop… And I should make a distinction here between sort of the cleaner burning of fossil fuels here in the United States where we’ve got scrubbers that capture the sulfur dioxide. That was passed in the 1970s, the Clean Air Act, to prevent acid rain, other problems. And so we’re already sort of capturing that sulfur dioxide that generates these aerosols, but there are other areas of the world where they’re not doing that. There’s dirtier coal burning. And that, if we shut down fossil fuel burning, including coal burning, then those aerosols disappear. And so you get some extra warming out of that. So you get some extra warming out of that, but you offset that if you bring methane down and some of these other shorter term greenhouse gas, and it’s all sort of in the wash. All those things also sort of cancel out as well. And so you’re not too far in the end from the picture that I presented.

Laura Helmuth: Great. Thank you. And quickly, for this to work for the potentially two to three year stalling and potential reversing of some of the climate emergency effects we’re seeing already, do we need to stop carbon dioxide emissions immediately? Is it an all or done thing? How do changes that are happening now affect the trajectory of when we get to 1.5 degrees warming or two degrees.

Michael Mann: Yeah. Great question. And it’s all tied together. We talk about if we want to limit warming below one and a half degrees Celsius, three Fahrenheit, we’ve all heard these numbers now, we’ve got to bring carbon emissions down by 50% within this decade. So we’ve got to come down the other side of the mountain. The good news is we’re sort of riding along the summit now. Those carbon emissions are no longer rising, but we’ve got to bring them down and we’ve got to bring them down quickly. We’ve got to come halfway down the mountain in 10 years. And the reason we know that is because of the concept of the carbon budget, which is based on the science that we’re talking about. So it all comes together to tell us that if we want to prevent the surface temperature of the planet, the average surface temperature from crossing that dangerous one and a half degree Celsius threshold, we’ve got to reduce carbon emissions by 50% within this decade.

Michael Mann: And that has been informing very prominently the discussions, for example, in Glasgow. COP26 policy right now is being driven by this understanding that’s where we need to get to. Halfway down by 2030 and all the way down to zero, the bottom of the mountain by 2050.

Laura Helmuth: Great. Thank you. I’m sure people will have a lot more questions. And to remind everybody in the audience, we will have a Q&A as soon as we’re finished with the opening remark. So thanks so much, Mike. I’m going to turn to Mark now.

Laura Helmuth: Thanks so much, Mike. I’m going to turn to Mark now. And Mark, you and Mike and Saleem, you’re working on an opinion article. And I think we’ll be able to at least have a link to a teaser about this, but it focuses on the psychological, behavioral and social implications of this research. And I’ve got to say, at least the draft I’ve seen, starts out with a great lead, which is quote, one of the biggest obstacles to avoiding global climate breakdown is that so many people think there’s nothing we can do about it. And would you like to tell us a bit about some of the implications of this research? And how it can inform and change and advance how we think about it?

Mark Hertsgaard: Sure. I really do think this is a paradigm shift in the implications of climate science. I say that as somebody who’s covered the climate beat for 30 years now. And it was always seen as something that we can’t get out of. And I think these implications fall into what I call the “three Ps,” the psychology of climate, the politics of climate and the policy. The psychology is if you listen to what Mike says here, that to boil it down into a non-scientist terms, is that we can stop the temperature rise within three years once we zero out emissions. So that means that we’re not necessarily doomed after all.

Mark Hertsgaard: And I must say, as someone who talks to a lot of people about this, the first question that people often ask is, well, what can I do about it? And a lot of people don’t even get there because they said, “It’s just impossible.” In fact, when I was writing this piece with Mike and Saleem, I kept thinking about the teenage daughter of a good friend of mine. Who’s out there on the barricade? She’s carrying her sign, she’s marching and all of that as a high school student. But she came home to her dad one night and said, “Dad, I’m going to keep doing this but I’m not quite sure why. We’re doomed.” And this science is the answer to that. Is that it’s not a get out of geo free card. I see the comments in the chat. Yes, there’s a lot of stuff that’s still locked in. Yes, there’s going to be a lot of sea level rise. Yes, the oceans are going to keep warming. Yes, they’re going to keep us acidifying. There’s a lot of work to do. But if we lower the emissions quickly, we can get there. We can avoid the worst. So that’s the psychology.

Mark Hertsgaard: And because of that, I think that also potentially changes the politics because then people, instead of saying, “Oh, I’m not going to March anymore. I’m not going to vote. I’m just going to tune out and go make the best of it.” People will say, “Well, let’s get involved. Let me make sure I vote. Let’s go out and register people to vote. Let’s go out there and march in the street, let our local officials all the way up to national officials know we have an emergency here and we’ve got to do something about it.” And once you bring a lot of people into the political process, that’s how you get changed. Change does not come from the top. It comes from pressure from the bottom. All of history shows us this.

Mark Hertsgaard: And then finally the third P. If you change those politics and you change who gets elected and who gets voted out, then the policies that you can approach, that you can pursue rather become different. Right? Imagine if there were not a 50/50 split in the United States Senate right now, but rather the Democrats had a majority. You would’ve had Build Back Better legislation already. What if they had a really strong majority, you could have even had a Green New Deal legislation, what really is needed, that level of emergency response. So those are the three things that I think can really change, all three Ps, the psychology of it, the politics of it, and that changes the policies.

Laura Helmuth: Nice. And you mentioned young people being very engaged and facing this head on and recognizing that what we do now will have huge implications by the time they’re middle aged or beyond, or by the time they have kids. Could you talk a bit about how this different understanding can help journalists especially reach that audience? And how do you think this could shape how younger people especially are interested in climate? How they can understand their options and what the implications are?

Mark Hertsgaard: I think we know here at Covering Climate Now from looking at the social science research, that what people in general, not just young people, what they want from journalism is not just, “Oh, it’s bad bad bad.” Not doom and gloom. They want also, what do we do about it? So there’s a whole school of thought and practice in journalism called solutions journalism. Now, let me make it clear. This is not cheerleading. This is not activism. This is not saying, “Oh, we got to go do this and campaigning.” Rather, it is telling the whole story. It is telling what the problem is but also what the solution is. The social science research shows that people are very tired. Average people when they look at the news, it’s all bad news. If it bleeds, it leads. I’m tired of that. So they tune us out. Right.

Mark Hertsgaard: Whereas if you give them the whole picture, yes, there’s a problem here, yes, the earth is overheated now, but here’s how you fix it, that not only makes them want to get involved, but speaking candidly as a journalist, it builds our audience. Right. They’re going to come back. They’re going to watch your show. They’re going to read your stuff. So I think that’s the opportunity here for journalists is to recognize that our coverage will be both more true to the science and more helpful to our audiences and to, frankly, humanity’s survival. If we tell the whole story, including the good parts.

Laura Helmuth: Yeah, yeah. Absolutely. That is the challenge of our careers is to not be unremittingly grim, to be honest and completely clear about what’s happening, but not make it seem hopeless or reveal in which ways it’s not hopeless. So thanks for spelling that out so nicely. So again, there’s some great questions, great ideas in the chat, and we’re definitely going to get to a lot of those in the Q&A.

Laura Helmuth: But I want to go now to Saleem for some opening discussion. And thanks so much for joining us. Thank you for joining us. You’re coming to us from Bangladesh. Really glad you could make it. Thanks for staying up late. Could you speak a bit about some of the work you’ve done in Bangladesh and in general about helping representatives of what we call the global south, which doesn’t mean necessarily countries in the Southern Hemisphere. It’s referring more broadly to some of the countries that are, I think, suffering the most from the climate emergency, but the least responsible for it. How does this science influence the message and the policies that you think will be most important for the global south?

Saleemul Huq: Great, thank you very much, Laura. And thank you for organizing this event and inviting me. And greetings from Dhaka Bangladesh, where it’s nearly midnight here. So I’ll segue off Mark’s last comments in that my country Bangladesh is one of the biggest victims of the impacts of climate change, one of the most vulnerable. And if anybody had a right to be doom and gloom, it’s us but we are not. We have been facing climate change for the last decade. You guys have just started hearing about it but we’ve been facing it. And we are facing it successfully. We are dealing with the impacts of climate change from 1.1 degree centigrade that is already happened due to human-induced climate change. Staying below 1.5 is a goal. But dealing with the 1.1 that’s already happened is reality for us. And it’s going to be reality for you as well.

Saleemul Huq: And so in our case, we are now finding ways to tackle it. And as Mark says, we are in the solution space to the problem, not in the problem space of the problem, not dissecting the problem endlessly, but finding solutions to the problem. And in Bangladesh, 170 million people living on a Delta of two of the biggest rivers in the world, the Ganges and the Brahmaputra, regularly flooded, regularly hit by cyclones. We are leading the world in adaptation to climate change. And specifically what we call locally-led adaptation by the people themselves. The most vulnerable people in Bangladesh now are the best adapters in the world because they are facing the problem and they’re tackling the problem, then solving it. It’s still happening. We still get the floods and the cyclones but they don’t defeat us. And we are resilient and building our resilience to deal with them. And that’s a lesson that all countries will have to learn because all countries are going to be hit, even if we are able to bring the emissions down quickly and stabilize the temperature goal.

Saleemul Huq: Nevertheless, we are going to face impacts in the near term. All countries are going to face them and all countries are going to have to learn to adapt and also face, now increasingly, what we call loss and damage from the impacts of climate change, which we will hear about, I’m pretty sure, in the upcoming Working Group II report of the Intergovernmental Panel on Climate Change, coming out in a matter of days. It was discussed in COP26 in Glasgow. We didn’t get it resolved, but it is an issue that’s not going to go away. We’re going to have to deal with it.

Laura Helmuth: Great. Thank you. Yeah, it’s really inspiring. And I think it’s an opportunity for journalists in other parts of the world to show what we can learn from Bangladesh and from some of the places that are adapting necessarily fastest and most creatively. So you were very closely involved in the effort to insert the 1.5 degree target, 1.5 to receive warming or less into the Paris agreements back in 2015. Since then, global emissions have continued to rise. We’ve gotten some pledges, not enough and not as much action as necessary. When thinking about this revised understanding of the science, do you think from a policy perspective, do you see potential for it to spur better action? Or do you think it’s going to be used to justify dawdling with climate commitments? How do you think this could play out in the policy world?

Saleemul Huq: Well, I’m quite disappointed by the policy world. As you mentioned, we had an agreement in 2015 in Paris. That was the height of the achievement of the global policy discussions under the UN Framework Convention on Climate Change. But since then we’ve just seen dawdling. And even at the latest Conference of Parties in Glasgow, we didn’t get the progress that we wanted. The vulnerable countries went to Glasgow asking for the Glasgow outcome to be called the Glasgow Climate Emergency Pact. And what happened in the end? The United States and the UK and the other rich countries downgraded it to the Glasgow Climate Pact. The word emergency was removed. The feeling of emergency was not felt and they don’t feel the emergency.

Saleemul Huq: And I agree with Mark. It’s their kids who are going to make them feel the emergency because they’re old people. And this is true for all countries, including my own, the old people don’t get it, the young people do. And so we are going to have to change from the bottom up. The young people are going to have to change the elders to make the changes that are necessary and needed because the elders have failed us quite clearly. Thirty years of failure, of not heeding the advice from the scientific community.

Laura Helmuth: Great. Thank you. And one more quick question before we turn to the audience questions. I’d like to think one of the reasons that Bangladesh has faced climate change relatively creatively and with a lot of effort and a lot of experimentation is that journalists are very engaged in covering climate. Would you say, have you noticed that in Bangladesh that… are there lessons for journalists around the world about climate coverage that you’d like to share?

Saleemul Huq: Absolutely. So it’s midnight in Bangladesh. And I’ve already seen in the chat box, a number of Bangladeshis who have tuned in for this session, including journalists. It gives you the level of interest here. I’ll give you an anecdote about the level of awareness in Bangladesh about climate change, which I claim I have no basis for this claim that is the highest awareness in the world on climate change. People in Bangladesh know what climate change is.

Saleemul Huq: And I’ll give you one anecdote when we were in Glasgow in the COP, it’s a two week long event. We had the leaders come for the first day. We got all the media come to cover the leaders. Joe Biden was there. Boris Johnson was there. Prime Minister Hasina was there. The journalists all came, covered the leaders speeches, and then the leaders left and journalists all left. Then there were two weeks of negotiations. Now from Bangladesh, there were three private television channels who sent journalists to Glasgow, and each of them were broadcasting live from Glasgow every single day to a very general audience in Bangladesh, of people who were following the negotiations every single day. They were following who said what on which topics, until the very end, when the rest of the world’s journalists came for the very end to just cover the end of the story. The Bangladeshi audience, the people in Bangladesh were following it on a day-by-day track.

Saleemul Huq: I don’t think any other countries, people not even in Glasgow, in Scotland or in the UK, who was hosting the event, actually followed it in the detail that the Bangladeshi people were able to do and journalists in particular played a big role in doing that.

Laura Helmuth: Oh, that’s great. That’s great to hear. And I hope that helps all of us in the audience make a pitch to the editors and owners of our publications to do more. People want to know. So I thank all three of you for your opening comments. We’re going to shift to the Q&A now, and I know there are a lot of questions. So thanks for responding to journalists who want to know a lot, who want to know everything, which is inspiring. But hopefully we’ll get to most of it. And Mark, do you want to lead this next part?

Mark Hertsgaard: I will. Let me quickly respond to a couple of things in the chat first. And let me give a heads up to Craig. Craig Miller, we’re going to be calling on your question next, but I’ve seen from a couple of people asking, is there a paper. And yes, Michael Mann and Saleemul Huq and I have co-authored an opinion piece. We are shopping it around. If your news outlet is interested in running it, we haven’t placed it yet. I’ll not say who is considering it, but I will say that it is still up for grabs if you want to put in a bid. I don’t mean a bid in terms of price, it’s for free. But so that is coming.

Mark Hertsgaard: And I also saw a question here about how the fact that this science was included last August in the IPCC report, but buried, but included makes it tricky to report now. And I would just say to my journalistic colleagues, with all due respect, we have got to get over this idea that because something appeared someplace and is not new that somehow it is not news. News is not just what is new. News is also what is important. And if something was missed and we missed it, our audiences should not pay for that by us keeping that information from them. We should rather, we should rectify that as soon as possible. That’s what Saleem and Mike and I are trying to do with our paper, what Covering Climate Now is trying to do today.

Mark Hertsgaard: We urge everyone, all the journalists on this call, please write about this. So, those two things, and we are now going to … So keep the call, sorry, keep the questions coming in the chat. Some came in over RSVP, including this one from Craig Miller. Craig, if you’re there, you can please now unmute yourself and then you should be able to be heard by everyone. So, I turn it over to Craig Miller. He’s with PBS News.

Craig Miller: Okay. I think I’m unmuted now.

Mark Hertsgaard: You are. Yeah.

Craig Miller: I submitted my question, Mark, before this event, and now I have so many more, I don’t know which ones to prioritize.

Mark Hertsgaard: Stick with that first one. That’s a good one.

Craig Miller: I hope somebody will ask about carbon sinks. But Mike, you might remember a few years ago, you and I did an interview, which was memorable for me because I asked you point blank, does this mean we are screwed already by climate breakdown? Which is the new term that I’m using. And you basically said yes, it’s just a question of how screwed we want to be, would determine how we move forward. Have you changed your position on that in light of this new science? And how do scientists like yourself balance telling the hard truths with not wanting people to give up hope? Because I worry a little bit about the potential emergence of what you might call wishful science.

Michael Mann: Yeah. Thanks, Craig. It’s good to hear from you. Indeed in my messaging, and I think we heard that with Saleem and Mark as well, it’s really about communicating both the urgency, and the urgency is very clear, but the agency as well. There are various versions of that statement that you quoted. I think when I talked to you, I used one word. In other contexts, I’ve said that it’s not whether or not we are F-ed, it’s a question of how F-ed we are. And what I mean by that, and that still very much applies, if you’re Bangladesh, if you’re Puerto Rico, if you’re California, Australia, Florida, an increasing number of places around the world, you’re seeing the devastating impacts of climate change now. We can’t avoid climate danger, climate damage because it’s here, but what we can do is try to limit that damage.

Michael Mann: This latest science really does reinforce that narrative. What it tells us … And I say this latest science. It’s 10 year old science, but our full appreciation of the implications of that science tells us that there is this direct and immediate impact of the actions that we take today to lower carbon emissions. It very much translates to implications for the policy discussion as well. So no, I haven’t changed my views at all. If anything, I think I’ve just clarified the reason for them.

Mark Hertsgaard: Thanks, Mike. I’m going to take the liberty of channeling a question from my dear colleague at NPR, Neela Banerjee, and then I will ask James Conca of Forbes to speak up. But Neela asks, I think a very pertinent question here, and maybe you know the answer to this, Mike. I’ll hazard one too, which is why was it that this very important science was included but buried in the last August IPCC report, the working group one report? How and why did that happen?

Mark Hertsgaard: I’ll just remind people that as a journalist covering it, even though I knew the science, because Mike and I had been talking about it, I didn’t know it was in that report until after I talked to people like Mike and others. Why was that? I think part of it might be something you said to me, Mike, at the time, which was sometimes scientists don’t realize what everybody else doesn’t know. That’s partly on the scientists and it’s partly on us as journalists. It’s our job to pull that out. But Mike, do you have any inside knowledge about why this revised science wasn’t made more of a big deal of in the last August report?

Michael Mann: Yeah, it’s a great question, and I think exactly what you say, sometimes we don’t necessarily connect the dots. We can jump from point A to point B based on our scientific knowledge and expertise, so we skip steps. It’s like in homework back in high school, if you didn’t show your work, sometimes we don’t show our work, and maybe we should be docked some points for that. Part of that is this fact that the reason we can talk about a carbon budget, why can we do that? It’s because of this understanding. It’s because of this revised understanding.

Michael Mann: I was going to mention one more thing. Sometimes an analogy can be very powerful. One analogy I like to use here is carbon levels. The CO2 concentration in the atmosphere is like the water level in your sink. If you have the faucet on and the drain closed, that water level is rising and it’ll continue to rise. As long as that situation is there, the CO2 will continue to rise. When you turn off the faucet, it’ll stop rising. That’s a fixed carbon dioxide concentration. But actually we’ve got the drain open. The drain are those natural sinks. So the faucet is off and the drain is opening. That means the water level’s going to come down. That’s really the crux of the carbon cycle dynamics, if you will, the technical term that we use for that. So we were for too long communicating the analogy of the faucet being turned off and the water level stops rising, but we weren’t talking about the drain being open, and that’s a critical component of it.

Mark Hertsgaard: That’s a really helpful analogy, Mike, I thank you for that. We’re going to go to the Forbes question, but first, just quickly to you Saleem, you mentioned how much more knowledgeable and interested both journalists and the general public in Bangladesh are in climate stuff in general. My question is, would this revised science, is this news in Bangladesh as well, or do people already understand this?

Saleemul Huq: No, I think this is news in Bangladesh as well. It’s fairly new for me as well. I’m not a climate scientist, Mike is. I defer to Mike to tell me what’s happening on the climate side, but I work on the impact side. And to give you another hidden element of the AR6 working group one report, which said that climate change was unequivocally now happening and we are seeing impacts, that was, again, something that in my view, didn’t get publicity enough by the journalists. We certainly didn’t get reaction enough by the policy makers in COP26, because we are now suffering loss and damage from human induced climate change that is now attributable scientifically to the fact that we have raised temperature by over one degree because of the emissions of greenhouse gasses. And countries like Bangladesh have been suffering this for a long time, but even you in the United States are suffering this now as a result of this increase. That to me has not been well reflected in the coverage of the science of climate change from the IPCC reports.

Mark Hertsgaard: Thanks, Saleem. Again, just quickly that’s Saleemul Huq. He is with the International Centre for Climate Change and Development in Dhaka, Bangladesh. Also with us today, Dr. Michael Mann of Penn State University and my esteemed colleague at Scientific American, Laura Helmuth. I’ll just remind people based on what Saleem just said, the next IPCC report is coming up February 28. Let’s learn from our mistakes on the last one. One way to do that is to interview scientists in advance of that report and then immediately after, and find out what they know from the inside of it. Don’t just listen to the press briefings and the press releases. Talk to a few journalists. Sorry. Talk to a few scientists about this.

Mark Hertsgaard: Come to our website, by the way, Covering Climate Now. We have a whole science vertical there that you can read background and some of the scientists to talk to about this to get yourselves up to speed in order to cover this February 28th report, and of course the report in March. Now, I’m going to turn to our colleague from Forbes, James Conka. I apologize if I’m mispronouncing your name, but please unmute yourself and go ahead.

James Conca: Excellent. Thank you. No, perfect. Perfect pronunciation. I think you’ve already answered it. With the atmospheric half life of CO2 at about 30 years, actually up to 300 depending on the mechanism of removal, you’re saying that when we stop increasing emissions or when they stabilize and start dropping, that the temperature was stabilized. So even with that long of a half-life, you still think it’ll stabilize fairly quickly?

Mark Hertsgaard: Mike, why don’t you take that?

Michael Mann: Yeah. Again, we don’t often do the best job of communicating the fact that the carbon dioxide in the atmosphere is building up at about half the rate we would expect. If all of the activity, fossil fuel burning and other carbon pollution generating activity, if we total up everything that we’re emitting into the atmosphere, the concentration in the atmosphere is only rising half as fast as we would expect. That’s because these natural sinks of the terrestrial biosphere, plants on land and the oceans have been taking up about half of that carbon. So, it is implicit, whenever we talk about the ocean carbon cycle, this chemistry, this physics is part of it. So what it tells us is that the carbon dioxide concentrations do slowly come down as the ocean absorbs that carbon, as the terrestrial biosphere absorbs that carbon.

Michael Mann: Now here’s the problem, and we’ve already seen some reference to this. That actually means that ocean acidification, which is from the atmospheric CO2 that’s going into the ocean, acidifying the ocean, that continues to get worse. Ocean warming, deep ocean warming continues on. That destabilizes ice shelves. It contributes to sea level rise. Again, as Mark said, this isn’t a get out of jail card. There is some additional damage that is locked in, and we’re going to need to deal with that. That means adaptation and resilience.

Michael Mann: Just one more comment. The breakdown in discussions at Glasgow were complicated. Part of the problem was actually, surprisingly it wasn’t the typical industrial countries, it was India, a developing country, that very late in the game went back on the agreement and said, “No, we’re not going to commit to phasing out carbon language. We want a phase down.” Now you could blame India, but that would be wrong because I think part of what India was doing is sending a message that look, the industrial countries haven’t ponied up. They haven’t provided the resources that they had promised to the developing world to help them grow their economy in a carbon friendly way to deal with and mitigate the impacts that we’re now feeling. So there was some real politics going on there. And the industrial countries, the G7, G20 countries really do need to step up their commitment to the rest of the world if we’re all going to come together on this. The good news is we’re going to revisit that in less than a year. We’re not waiting five years this time. The COP26 commitments will be revisited within a year.

Mark Hertsgaard:
Yes, they’ll be revisited at COP27, which is taking place this coming November in Egypt. The head of Egypt’s government just said the other day that indeed this whole question of social justice and the global north paying its fair share to help countries in the global south turn away from fossil fuels will be a primary focus. Laura, you have a question that I think you’ll have to call on.

Laura Helmuth: Yeah. There’s a question from Lyndsey Layton from the New York Times in the chat that a couple of other people in the chat have echoed, which is, I think this is for Mike, that the climate commitment assumes in a way that sinks will keep absorbing CO2, but isn’t it the case that a lot of things that we’ve thought of as sinks are turning into actual sources of CO2 rather than sinks?

Mark Hertsgaard: Excellent question.

Michael Mann: Yeah, great question. That is a worry, for example, with some of the terrestrial sinks like the Amazon. Some of you may have seen some articles about this, given warming and drying and deforestation, a combination of climate related and other human caused impacts. We could see, for example, the Amazon, which traditionally has been a huge terrestrial carbon sink, actually become a source. That’s problematic. The oceans ultimately can become saturated with carbon and become less and less effective a sink. That’s the bad news. The good news is that that is incorporated into these global carbon models. So, that physics in chemistry is in there. There isn’t an assumption that these sinks will remain as efficient as they are today. Part of what you’re talking about is built into the representations of the chemistry and physics in these models, but there is uncertainty.

Michael Mann: There are a lot of different processes that are impacting the global carbon cycle. Often you have large positive and negative numbers that happen to cancel out. Whenever that’s the case, that means there’s the potential for a lot of uncertainty. Those different contributions could change in different ways from how we project them to. So, there’s a lot of uncertainty and it’s not our friend. Again, we can’t rest on our laurels. As Mark has said, this isn’t a get out of jail card, but what it likely does mean is that we’ve got more time than we may have realized to try to do something.

Mark Hertsgaard: Thanks, Mike. I’m going to be turning in a moment to Jonathan Levy with the Radio Hub, but I’ll just mention to people here, this stuff is complicated. We’re trying to do all this in an hour, and it’s a great start, but we will be providing resources on our website for you to dig in deeper. I love to hear the constructive skepticism that is coming through in some of these questions. That’s exactly our job as journalists, and let’s just keep at it. But the main point here, let’s not forget, is that it is still possible if we move quickly. Jonathan Levy from the Radio News Hub, please unmute and ask your question.

Jonathan Levy: Thank you. It’s Jonathan Levy. I spent an intense two weeks at COP26 as well, talking to some of the IPCC authors and others. I guess first of all, picking up on the point that you were just making, we’ve still got a long way go to achieve net zero, so we have to strike a balance at the way we report the fact that we may see reductions coming more quickly than we previously…

Mark Hertsgaard: We may see reductions coming more quickly than we previously thought, so that’s just a thought there. My question is really about sea level rise. When I spoke to the World Meteorological Organization and others, they’re all using this expression “baked in” with sea level rise, probably more so than we might see things drop in the atmosphere. What are you seeing from your perspectives, and a lot of the scientists are actually debating between themselves at how bad sea level rise is going to be and some feel the tipping points and other accelerators are seeing increased melt in Antarctica and Greenland. Are you going to revise these down, or do you think these are still a very serious and real threat, which could be much more substantial than some of the more conservative estimates?

Michael Mann:Thanks. Yeah. Great question, and the reality here is that there is a huge amount of uncertainty when it comes to how close we are to tipping points impacting the disintegration of the major ice sheets, the western Antarctic ice sheet, the Greenland ice sheet, and we see the ice shelves becoming destabilized. These ice shelves prop up the inland parts of the ice sheet so when they disappear, many of them would be melted from below. Then the inland ice can begin to surge out to sea even more quickly. So there’s a huge amount of uncertainty and if you talk to different experts in ice sheet modeling and sea level rise, you will find a wide variety of views, a wide range of views on this, which speaks to the fact that there is a lot of uncertainty, and we’re not fully confident that we have all of the relevant processes represented well enough in the models to be confident with those predictions.

Michael Mann: So once again, uncertainty isn’t our friend here. There is the potential, and we have seen that when it comes to ice sheets and sea level rise at every juncture. As our understanding has improved, we’ve been talking about the potential for larger amounts and more rapid amounts of sea level rise, and so you have to understand those caveats. It’s still relevant to say that our best understanding is well represented by the conclusions of the most recent international assessments, the most recent IPCC Working Group one assessments, and the consensus represented in that report is that if we keep warming below one and a half degrees Celsius, that number we all continue to talk about, we can probably keep sea level rise about a meter to under a meter, meter and a half. That’s bad. That’ll be massively destabilizing, but we can probably deal with that, especially if it takes a century or more to happen.

Michael Mann: On the other hand, if we blow past that one-and-a-half-degree Celsius limit, then we have to start talking about 2, 3, 4, 5 meters of sea level rise. How quickly can that happen? Again, at every juncture, we’ve learned that these systems are more dynamic than we had envisioned and things can happen faster than we had envisioned, and so there’s a reason for concern and it underscores once again the importance, the urgency of taking action now. This is a minefield. It’s not a cliff, it’s a minefield we’re walking out onto and we have to stop that forward lurch because we will encounter more and more of these potential tipping points and disasters.

Mark Hertsgaard: Thanks, Mike. Just to clarify, when you say that the idea that if we keep it to 1.5 degrees temperature rise, that we could limit the sea level rise to a meter, meter and a half. Is that over the next hundred years, or are we talking about the next millennia because most of the scientists I’ve spoken to say over the next millennia, it’s going to be a heck of a lot more than a meter and a half.

Michael Mann: Yeah. Again, this is, most of these projections are looking out to 2100 or so, but if you look at the underlying studies, there are studies that suggest that we haven’t yet past that tipping point where we commit to the collapse of most of the west Antarctic ice sheet. So there’s a certain amount of additional warming that’s still left for us to commit to that. Exactly how much, is it one and a half? Could it be less? Again, uncertainty isn’t our friend here.

Mark Hertsgaard: I’m going to turn to Ian James in a moment, but Saleem, I have to ask you first, we’re talking about sea level rise. You were kind enough some years ago to invite me to Bangladesh and we were down there at the southern edge of Bangladesh for a while, which is arguably the most threatened place in the world by sea level rise because it is so flat. As you mentioned, the two of the biggest rivers in the world, huge Delta. You can look out for 30 miles and it’s flat as a pool table, and already then, that was 10 years ago. The rice fields, the rice yields were going down because the influx of seawater was making the soil salty. So for Bangladesh, even a meter and a half, very populated country, how do you deal with a meter and a half of sea level rise, even with all of the adaptation skills and tenacity that you all have?

Saleemul Huq: That’s a great question, Mark. So the answer to the question about sea level rise, speaking from the front lines where I’m located is that it is very location specific. So what Mike was talking about is global sea level rise from melting of the ice sheets, et cetera, but in every single location, the actual local sea level rise will have to take into account what the land is doing. If the land is stable, you get a certain amount of sea level rise. If the land is subsiding, which is a case in much of the Delta in Bangladesh, then you’re getting an additional increase of salinity into the soil, which you just mentioned that we are having here in Bangladesh, and so in crude terms, the cost of Bangladesh has three major sectors. The southwestern part is the mangrove forest, the Sundarbans, the biggest mangrove in the world where there’s not much we can do. The plants are there.

Saleemul Huq: Sea level rise is happening. Salinity is intruding. The salt tolerant varieties of trees are surviving and the salt intolerant varieties are getting decimated and we are having quite a significant ecosystem impact in the mangrove. Then in the central part, which is the delta of the rivers, the two big rivers that I mentioned, that’s what you’re talking about. Highly populated, densely populated, highly dependent on rice cultivation, but the good news is that our rice scientists have come up with salt tolerant varieties of rice and if you were to come back and visit that area, you would find millions of farmers on millions of hectares growing salt tolerant varieties of rice produced by our scientists, our rice breeding scientists, and produced and sold by the private sector companies and farmers buying them at a higher price than the traditional varieties, willing to pay that higher price because they survived the salinity levels.

Saleemul Huq: And we are now still able to grow rice. Now there’s a limit to how much that can be done and your question about the one meter, one and a half meter, at certain point, we simply will not be able to adapt and cope and people will have to move and we will see what we now are beginning to see, our climate migrants leaving the low land coastal area and ending up in the cities like Dhaka City, and in fact, we are trying to promote the idea of developing what we call climate resilient migrant friendly towns, so that these potential climate migrants don’t end up in the slums of Dhaka, but go to these other towns where we create opportunities for them to stay and live and become citizens over time because it’s going to be inevitable. We cannot prevent a certain degree of climate migration over the coming decade or two. It’ll slow, but it’ll be inevitable and we have to deal with it.

Mark Hertsgaard: Thank you, Saleem. I’m going to be really quick here. Ian James, please ask your question and it’s going to be for Mike Mann about the next IPCC report, and then we must close. Ian James of the Los Angeles Times.

Ian James: Yes. Thank you. So looking ahead to the February 28th report, how do you think the findings that you’ve been discussing, the direct and immediate impact of reducing carbon emissions, how do you see those insights connecting to the topics that will be covered in the upcoming report focused on impacts, adaptation, and vulnerability, and how do you think the latest science should translate into action and solutions?

Michael Mann: Yeah. Thanks, Ian. A great question. There is here in this case, a very direct relationship between the two working groups. There isn’t always, but in this case, the basic science that tells us about how much of a warming commitment we have also informs so many of these impacts that we’re seeing. Some of them, as we said, the ocean warming, the deep ocean warming will continue on, sea level rise will continue on, but many of the extreme weather events that we’ve seen, the unprecedented heat waves and wildfires and floods and superstorms, those are tied pretty closely to the surface warming, and so that tells us a lot. We already are dealing with those impacts, those devastating impacts, but there is the potential to prevent them from getting much worse by limiting the warming, and so I think that understanding, I haven’t seen the final working group two report yet.

Michael Mann: But the dirty secret that many of you are probably in on is there can’t really be any true surprises in these reports because they’re assessment reports. They’re based on the cumulative literature over the past several years, over the past five years, and so if you’re already immersed in that literature and a lot of you are, a lot of you are already immersed in the research into climate impacts, there won’t be surprises there. It’ll be the stuff that you already know being clarified and being hopefully characterized in a way that does reflect our best current understanding, but that’s the bottom line is that we’re already dealing with a new normal, if you like. That’s the best case scenario. We already have to deal with this elevated risk that we’re seeing now, but we can prevent it from getting worse and I think the report will make that clear as well.

Mark Hertsgaard: Thank you, Michael Mann of Penn State University. Thank you, Saleemul Huq of the International Center for Climate Change and Development in Bangladesh, and special gold star to you, Saleem, for staying up so late, Dhaka time. Thank you my esteemed co-moderator, Laura Helmuth, that’s Scientific American, and the Scientific American by the way, folks, is the exception to the rule. They had an article about this in October so go back and read that, and the op-ed piece that Mike and Saleem and I are preparing, we will certainly notify everybody on this call when we place that at an outlet, which we anticipate will be very soon, and finally, I would just say to everyone, this is, I hope this conversation today helps fortify you in your conversations inside your newsroom with your assignment editors and the gatekeepers who decide how big this story gets played.

Mark Hertsgaard: Make sure that the February 28 release of the working group two report is not buried inside. It’s not given 20 seconds at the end of the broadcast. We face a climate emergency, as Saleem was saying earlier, and we as journalists have got to be clear about that. That is what the science says. We as journalists should be following the science. So thank you all for being with us here today and we will be sending out all of the comments here in the chat later to all of you who participated. We will be sending a recording of this event and even if we can get it together, a rough transcript of it as well. So look for that in the coming hours and days, and beyond that, thank you again. On behalf of Covering Climate Now, I’m Mark Hertsgaard and we wish you a very pleasant day.