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| 00:00 | uh welcome everyone uh thank you for joining an intimate conversation with leading climate scientists to discuss groundbreaking new research on global warming uh particularly the uh the paper that is now live today on global warming uh in the pipeline I am pleased to introduce uh Professor Jeffrey saxs director of the center of sustainable development at Columbia University and president of the UN sustainable development Solutions Network who will be moderating uh this webinar so Jeff over to you thank you very much I I'm |
| 00:35 | really thrilled and I'm only going to speak for a moment because we have a very important paper and uh several of the authors of this important paper on global warming in the pipeline it's a complicated paper the message is extremely important uh but I think it needs all of the time of the scientists to explain uh this paper to us we're going to hear from uh several of the authors starting with the lead author James Hansen of Columbia University uh and of course the longtime lead climate scientist for the |
| 01:17 | US government and for NASA's Goddard Institute of Space studies uh and then we'll hear from several colleagues and uh and co-authors of this very important p paper we are just weeks before the world will gather in Dubai for cop 28 excuse me so the message of this groundbreaking paper is extremely important and Jim if I could turn it over to you uh to start us off uh I would be most grateful thank thanks very much Jeff and uh thanks to your people and and uh your program for hosting uh this discussion |
| 02:04 | we're honored and I I also want to if I can go to the next chart I want to thank my uh co-authors for their unique scientific expertise and contributions to this paper and uh the editorinchief uh of Oxford open climate change uh Bill Cole Rowling for inviting me to include my perspective about policy implications which is the final section of the paper uh going I have the next chart so the climate on our remarkable home planet is characterized by delayed response and amplifying feedbacks which is a recipe to lock in |
| 02:54 | intergenerational Injustice so we climate scientists have an obligation ation to explain this situation clearly as best we can especially to young people and to include the policy implications because if we don't include the implications people who have a special financial interest will make their own conclusions uh the next chart in 1979 the Charney report of the US National Academy of Sciences estimated based on climate models that Global Climate sensitivity was 3 degrees Celsius for double atmospheric CO2 but a very large |
| 03:46 | uncertainty soon thereafter it was realized that a much more reliable measure of climate sensitivity could be obtained empirically from the precise knowledge of glacial to interglacial CO2 to change provided by icore data but this empirical evaluation also requires knowledge of global average glacial to interglacial temperature change and that remained uncertain because of a misleading evaluation of glacial sea surface temperatures that persisted for 40 years the wrong assumption was that microscopic species in the |
| 04:33 | ocean surface layer would migrate as climate change so they would always be at the temperature they prefer today rather than partly adapt over Millennia to temperature change now recently Jessica Tierney and her then postdoc Matt Osman who is our co-author developed a global temperature analysis omitting the bi ology data but using widespread geochemical proxies Isotopes and Alan Seltzer used noble gas abundances in groundwater from last glacial maximum at latitudes 45 South to 35 North to evaluate uh global |
| 05:22 | temperatures glacial temperatures in our paper we show that the tyan Osman and celer analyses are consistent implying a glacial to interglacial temperature change of about 7 Dees Celsius so uh next chart we now know the surface temperature during the glass GL glacial maximum and the forcings that maintained the ice AG cold together these imply a climate sensitivity of about 4. |
| 05:58 | 8 degrees C for doubl CO2 ipcc's best estimate of three degrees is excluded with greater than 99% confidence this High climate sensitivity has major implications for global warming in the pipeline the next chart clouds which uh George will talk about in a minute are the mechanism in climate models that permits a broad range of climate sensitivities so the next chart oh know you have no I actually go back to the one that you just had uh so wait a minute if climate sensitivity is high how can climate models with a smaller climate sensitivity which is |
| 06:52 | most models obtain realistic global warming for the past Century the answer the second of the two important climate forcings aerosols are an unmeasured free parameter and models with low climate sensitivity can compensate by understating the aerosol cooling so can I have the next one so aerosols are are fine Airborne particulates they are a health hazard killing several million people per year aerosols also cool the climate by reflecting sunlight to space their main effect being as condensation nuclei for cloud drops they slightly increase cloud |
| 07:43 | cover and make clouds a bit brighter Humanity made a fan bargain by offsetting a substantial but uncertain fraction of greenhouse gas warming with aerosol cooling now now as we want to reduce all uh The Chronic health effects of aerosols our first fian payment is due the payment is acceleration of global warming next chart China reduced its aerosols in the past 15 years and aerosols from ships decreased in 2015 and especially in 2020 as Leon will describe in in a few minutes so we expect the post 2010 global warming rate to increase at |
| 08:40 | least 50% which is the lower edge of the yellow area if we are right the 12-month running mean temperature will rise above the yellow region by next spring as the current elal Peaks the mean temperature for for the rest of this decade will be at least 1.5° celi warming and 2° Celsius global warming will be reached within 20 years thereafter the next chart although U aerosol climate for although aerosol climate forcing is unmeasured there is a great inadvertent aerosol EXP experiment now ongoing that helps to educate us the international |
| 09:35 | Maritime organization imposed regulations on the sulfur content of ship fuels in 2015 and tightened the regulations in 2020 in 2020 this should have a detectable effect on clouds decreasing cloud cover and Cloud brightness and thus increasing the sunlight with absorbed by Earth especially in the North Pacific and North Atlantic regions where shipping is the source of a large fraction of the sulfate aerosols the next chart the satellite data which Norman uh will talk about suggests that absorbed solar radiation is |
| 10:22 | increasing it's highly variable because of natural variations of cloud patterns such as the Pacific decal oscillation but since the strong regulations on ships went in effect in 2020 solar radiation absorbed by Earth has increased about 3 watts per meter squared in the North Pacific and North Atlantic next chart on global average the solar radiation absorbed by Earth has increased about one watt per meter sare squ the next chart this increase of absorbed solar radiation is the reason that Earth's energy imbalance |
| 11:14 | has almost doubled since 2015 when I gave a TED Talk uh more than a decade ago Earth's energy imbalance was about 6/10 of a watt per square meter which is equivalent to 400,000 hirosima atomic bombs per day that much energy being poured mostly into the ocean that imbalance has now doubled that's why global warming will accelerate that's why Global melting will accelerate now the next chart let's um let's look at the absorbed solar radiation ation again if this is not noise and I don't |
| 12:04 | think it is noise this one wat increase is a BFD a big deal let's compare it with greenhouse gas climate forces the next chart the greenhouse gas climate forcing on the next chart has increased about 0.045 watts per meter squared per year which is almost half a watt per decade so the one watt increase of absorbed solar R radiation is equivalent to more than a 20year increase of greenhouse gases at their current High rate of in increase that's why I can say with confidence that global warming will now accelerate let's first look uh at |
| 13:10 | greenhouse gases a several uh years ago ipcc defined a scenario RCP 2.6 aimed at keeping global warming less than 2 degrees Cel and pushker will comment on the modeling assumptions that lead to such uh drastically declining greenhouse gas emissions but the real world overshot the plan we could close the gap by extracting CO2 from the air but the annual cost now has reached 3. |
| 13:54 | 5 to7 trillion based on estimates of David Keith on uh CO2 extraction the cost of offsetting the decreased aerosol cooling would be 115 to $230 trillion conclusion the 2 de Celsius global warming limit is dead unless we take purposeful actions to alter Earth's energy imbalance the next chart the first thing uh that we must do is reduce emissions as rapidly as possible but fossil fuels are providing most of the world's energy almost 80% the next chart most of today's emissions and future emissions are from emerging |
| 14:54 | economies Nations that want to raise their living standards the next chart the task uh to reduce no actually let's go back one chart to the yellow and blue one um yeah as I said most up today's emissions are from emerging economy so we can go to the next chart the task is to reduce the carbon intensity of uh Global energy to near zero but we reduced it only from 08 to 7 in the past half century it's not plausible for it to go to near Zero by midcentury Sweden did well by decarbonizing its electricity in part by |
| 15:58 | building nuclear power plants now my last chart on the fundamental required actions none of these are occurring a rising carbon fee is the fastest most effective way to affect all uses of fossil fuels but the fossil fuel industry has prevented it in dead of east west cooperation our politics and special interests have led to a focus on economic and Military agomy which is foolish because we are all in the same boat and we'll s together if we don't work together I don't think that anyone asks young people if that if this |
| 16:56 | confrontational approach is the kind of world they wish to aim for the 1.5 degree limit is better than a door nail and the two degree limit can be rescued only with the help of purposeful actions to affect earth's energy balance we will need to cool off Earth to save our coastlines coastal cities worldwide and low lands while also addressing the other problems caused by global warming now it will take uh several years for socialization of uh what is needed for the public to understand which will be aided by the |
| 17:50 | increasing problems that they will see from global warming that several years will provide the time that young people need to understand this matter and specifically the fact that I believe a political party that takes no money from special interest is probably an essential part of the solution young people should not underestimate their political cloud thanks thank you very much Jim uh could you uh just before we turn to uh George uh just say a word about the 1. |
| 18:44 | 5 degree C uh Target and the two degree you said uh that it's it's dead could you just explain quantitatively what you mean by that to help people understand where we are and where we are heading right now well in the next several months we're going to go well above 1.5c on a 12 month average now as it we go from the El Nino to the linia it will drop back below the the yellow region that I showed in my chart and may fall as low as 1. |
| 19:23 | 4 to 1.3 but for the rest of this decade the average is going to be at least 1.5 we know that because the planet is now out of balance by an incredible amount more than it ever has been and you know it's doubled so you've got a huge amount of incoming energy that that's what causes the temperature change uh so 1. |
| 19:53 | 5 degrees is already uh is it's going it's going to be occurring in the next several months and averaged over the next several years will be at least that level if if there's more energy coming in and going out the planet is going to get warmer and we're already at that level and the uh so far as two degrees is concerned it yeah you you can see that the attempts to make a plan for how you could stay under two degrees we're shooting way over that and that was with without considering the effect of this additional imbalance caused by |
| 20:37 | aols being reduced so there's as Pusher will show that the scenarios that you would need to stay under two degrees are just not they're imaginary and the aerosol just complicates it further so uh we we can do it we we we will have to do it but it's going to require the combination of reducing emissions as rapidly as possible but also if we're going to avoid Antarctic you know there's a well I I shouldn't go into the details but if we're going to keep sea level close to where it is we actually have to cool the |
| 21:24 | planet we can't allow it to continue to be out of balance the way it is now because it's melting the ice shelves and we're going to lose the West Antarctic ice sheet if we don't cool the planet off thank you uh grim and we'll come back to this in uh the Q&A no doubt and in the conclusions but let's turn to George cudas at uh NASA's Gard Institute of Space studies who's going to talk to us about the cloud modeling that is part of the the the new insights showing this increased climate sensitivity so over to |
| 22:06 | you George thank you Jeff um so I'm GNA talk a little about uh clouds and the role in determining climate sensitivity um when we went from uh the older generation of climate models the Sim 5 models to the SIM 6 models one thing we noticed right away was that uh uh climate sensitivity increased and uh there was a big effort to try and understand why sim6 models are generally warmer than than the simic 5 ones and the chart on the left is is is showing you uh I think our best uh estimate that why this is happening uh what you see on |
| 22:47 | the left is the Sim um five models are the blue models this is the the change in Cloud uh feedback basically it's Cloud warming versus Cloud cooling so anything above zero is warming anything below zero is cooling so um you see that uh the blue models uh are cooler than uh than the red models or yellowish models which are the sim6 models mostly because of what is happening in the Southern Ocean because of what is happening south of 30 degrees south between 30 degrees and 90 degrees south uh where uh the new |
| 23:27 | climate models simic six models are warming the the planet a lot more uh than the simic 5 models so uh the feedback in the Southern Ocean is the main reason that the Sim uh six models have uh higher climate sensitivity than the Sim 5 models well now the question that uh we need to resolve is uh because what I'm showing you here the line is the the average of a number of models some of them have higher sensitivity some of them have lower sensitivities so I'm showing you the average which uh takes into account all of them the |
| 24:04 | question is Which models are more reliable uh which ones are the ones that we can believe uh more than than the others so uh we're focusing on the Southern Ocean to try and understand how well the models are doing clouds in the Southern Ocean and this is what the the chart on the right is showing you uh so the chart on the right is showing you uh low cloud cover uh in the whole world basically going from 60 South to 60 North if you go from bottom to top for every month going from January to December and the the uh panel on the |
| 24:42 | left is the climate models that have high climate sensitivity the panel in the middle are climate models that have low climate sensitivity and the panel on the right is observations so basically uh what you want to do is compare the panel on the right with the two panels on the left and see which one you believe more uh well just by looking first of all at at the colors which are showing you the the cloud cover you will see that the panel on the left resembles a lot more of the panel on the right than the middle one |
| 25:16 | the middle one seems to have a lot less uh low clouds uh throughout uh the globe uh than the than the observations or the on or the high climate sensitivity model so the high climate sensitivity models are making low clouds a lot better than the low climate sensitivity models and and uh any modeler would would would trust the model much more when it's more realistic not only do they make uh better low clouds the high sensitivity models but they also make the seasonal variation better for example look at how |
| 25:52 | clouds change uh with uh with the season on the right in the observations uh in the Southern Ocean which is the the the area that we want to focus most you will see that the observation shows that uh clouds increase in uh in uh the northern hemisphere summer basically uh June July August uh from May to to August or September uh and they decrease in in the two uh between uh January and March and and after September so uh if we look at the models the high sensitivity models they do the same thing they increase |
| 26:27 | their cloud during uh during the summer season the northern hemisphere summer however the low sensitivity models are doing the opposite they decrease their clouds not only they don't have the right amount of CLS but they also decrease them uh at the right at the long season so uh this is telling us that the high sensitivity models are doing a better job uh of producing those clouds that according to the left panel are really important uh in order to to understand climate sensitivity so this is why we believe that sensitivity is |
| 27:02 | around uh even above 4.5 those High sensitivity models have sensitivities about 4.5 degrees Celsius uh sensitivities above 4.5 degrees are are uh better are more reliable as far as climate feedbacks are concerned and just one last point to make here is that you see here that I'm trying to understand this by using seasonal variability because with Seasons things change a lot we need a lot more detail in our Cloud observations in order to take the last 40 years and and understand the changes over this this |
| 27:41 | time period however uh the way we're going is we're reducing the um basically the funding spend and and the and the um missions the satellite missions that are needed in order to try and understand this this CL Cloud feedback and cloud and neosol interactions and this is something that's worrisome we are at a very uh critical position at a very critical time uh we need to make decisions fast about our future and at the same time we're reducing our capability to observe the planet uh the way that we in the detail that we need |
| 28:19 | in order to understand what is going on and this is uh to me uh a very uh counterproductive you order not to use a uh a wor policy to follow at this critical time reducing our our investment in observing the a from space is uh is uh is exactly the wrong thing to do George thank you very much uh very important and also alarming on uh both the dimensions of what you're finding and what we're not measuring let me turn to Dr pushkar Kara at the Columbia University climate school and I think pushkar you're going to talk about uh |
| 29:07 | the comparison of the new paper and the ipcc climate sensitivity estimates uh well somewhat related yes so going to be talking about the comparison of the reason basically why I integrated assessment models and ipcc mitigation scenarios plausibility so okay so uh just to make sure we're all on the same page just the I wanted to briefly describe the general framework of integrated assessment models shown here as a flowchart um uh the output of which is used to drive uh Global Climate models and generate mitigation scenarios uh these models |
| 29:50 | overall are useful of course uh but they contain in my view many dubious assumptions uh and the ones I'm going to focus on um here are technology availability and implementation and the bottom line This has led to an over Reliance in my view on unproven meth mitigation methods uh including large scale Becks or bio energy plus carbon capture and storage and Dax direct air carbon capture and storage and other negative emissions Technologies or carbon dioxide removal methods so in terms of just the core mitigation problem we face as a world I |
| 30:31 | think this figure from the ipcc report the the most recent one AR6 summarizes things very nicely it shows the cumulative emissions from existing and planned fossil fuel infrastructure alone uh on the left and um on the right the gray bar show the remaining allowable carbon budgets in the one and a half and two degree mitigation scenarios and so what we see from that is basically the accumulative emissions if we just look at existing and planned fossil fuel infrastructure they already exceed essentially the entire range that's um |
| 31:09 | consistent with the one and a half degree scenario and even a good chunk of the remaining budget associated with the two degre scenario so the clear and immediate implication of this is that existing fossil fuel sources fossil fuel in infrastructure must be either phase down or decommissioned outright and the plan projects essentially have to be cancelled so in terms of um uh the CO2 emissions that are projected by imams and used to generate um mitigation scenarios and drive Global Climate models um they show very this is another |
| 31:51 | figure from the same ipcc report they show very large increases in in very un certain uh negative emission sources uh that I mentioned in both the land and energy sectors over the next few decades across most scenarios at least especially on the stringent side the one and a half degree scenarios uh so this the basic problem with this approach is that it does not sufficiently address other conflicts with other environmental and social goals namely sustainable development food production water use and so on so in summary um in terms of reality |
| 32:30 | versus U mitigation scenarios and IAM there's good news and bad news on the bright side clean energy sources are uh very rapidly and substantially increasing all around the world uh especially in the countries we need them most uh namely the top CO2 emitters uh but the time scale of required growth of these sources in both the one and a half and 2C scenario sets seems unrealistic um um for example if you look at the increase just this past decade uh excuse me the increase that's required this decade in either the one and a half or |
| 33:07 | two degrees scenarios it has to equal or exceed the increase over the entire last three decades and meanwhile on the downside unfortunately fossil fuel emissions are of course still Rising with no peak in sight at least not anytime soon so um the can't hear you anymore we may have lost pushkar's connection okay I think we have uh uh in the interest of time because we are running a little bit late could I turn to Leon Simons of the club of Rome uh to talk about uh the changes of Maritime emissions and pushkar we're going to move quickly |
| 34:04 | to Leon if that's all right okay great thanks a lot uh to Leon Simons who will speak about International uh Maritime uh regul organization regulations and its implications for uh the aerosol emissions and those implications for the uh increase of increased rate of warming so Leon to you please thank you Jeff hi yeah so as push mentioned that greenhouse gas emissions are not decreasing but there's one thing that is decreasing as Jim already referred to and that's the sulfur emissions these are decreasing much |
| 34:47 | faster than uh anticipated because um health and environmental regulations are very successful um why is that important here I I copied here the uh the most important forcing Agents from the ipcc and it shows the the warming effect from greenhouse gases here and then the so the cooling effect from sulfur deoxide emissions up to 2019 and on the right you see the the global sulfur deoxide emissions and as you can see most of these emissions are over the Northern Hemisphere that means the cooling effect of sulfur is mainly Focus if that's and |
| 35:33 | that's the best estimate of the ipcc and our research shows that it's probably and you can see there's a very big uncertainty our research shows that the cooling effect is most likely stronger than the ipcc estimated and that but that's not the whole story because the cooling effect is even stronger over the Northern Hemisphere where seven of the eight billion people on this planet live than on the southern hemisphere of course because on the northern hemisphere is where all these part these sulfur |
| 36:02 | particles were emitted and as Jim already mentioned these these these particles they reflect sulfur is is inside the fuels when when it's it's taken out of the ground and when it's burned the sulfur enters the atmosphere and it reflects sunlight and it makes clouds brighter and longer lasting and bigger and which also reflects more sunlight and if you reduce these part this the the burning of these fuels the emissions will decrease and then the amount of so sunlight that's reflected will also decrease which makes uh more |
| 36:37 | sunlight being absorbed by the Earth and then increase that would increase the Waring or uh more accurately it will hide less of the global warming caused by greenhouse gases and this is one figure of the paper um this here you can see again the the is North America is Asia and they see the total sulfate emissions that's both from natural sources and from Human sources and here on the right we show uh the the emissions which are from shipping and then you can see that over half of the emissions both natural from |
| 37:16 | algae for example and from volcanoes more than half of these emissions of sulfur uh are over the North Pacific and over the North Atlantic are from shipping and that's before shipping regulations came into effect and here I showed it from the international Maritime organization the changes in how much sulfur is allowed to be in the fuels ships burn these are 50,000 very large ships transporting goods all over the world and in uh 2010 and 2015 you see that this is in the regions in the North in North Sea and around North |
| 37:53 | America these emissions were reduced but globally the big biggest uh reduction happened in 2020 when the the the maximum amount of uh sulfur that was allowed to be in the fuel uh went from 3.5% to 0.5% reducing the silfver emissions over the oceans by 80% here you can see the uh what that means from 1900 to 2020 this is the S shipping sulfur deoxide emissions in uh in thousands of tons and they see here they nose dived when these regulations came into effect on January 1st 2020 and here again the the map I've |
| 38:35 | showed before this is the satellite uh data from from NASA from the Ser series Mission um looking at at the at at how much sunlight comes in from uh and then at the top of the atmosphere how much sunlight comes in and then how much is reflected and that means how um then you can calculate how much much net radiation is absorbed this is the 48th mon month running mean you can see in this region and in in this red and this purple region the North Pacific and the North Atlantic as Jim already mentioned there's a big increase of about three |
| 39:12 | watts per square meter of of radiation so the that means that a lot a lot more sunlight a lot more heat is being absorbed and that and if you compare that to the southern hemisphere ocean there we don't see that so we we can compare these very large regions of about 30 million square kilometers and about 20 25 million square kilometers to this large region on the Southern Hemisphere and then we see that of course there's some increase because if the Earth warms that decreases cloud cover as push already as George already showed um and |
| 39:53 | then so there is some also on the southern hemisphere of the oceans there some decrease in increase sorry in in the amount of sunlight being absorbed but that's on the Northern Hemisphere that's that especially in recent years it increased much more and there's some there's some variability uh which is more related to the to to El Nino and to the um to the Pacific Decay osculation maybe Norman can me talk about that a bit because um they found in already in 2021 that the rate of global warming had had doubled |
| 40:27 | both from Ocean heat content data and from satellite data from the same satellite data but um that they also um looked at the at the at this effect but now we see while we expected it to start decreasing because of L sorry and and the negative video um it started increasing instead and what does it mean for the the world as a whole that means that more sunlight is rapid there's a very rapid increase in how much sunlight is being absorbed that's in yellow and then in in red that's outgoing uh infrared or heat radiation and the |
| 41:08 | difference is the net imbalance or the Earth's energy imbalance so how much energy is accumulating on Earth in the earth system and as Jim already mentioned that has has more than doubled even especially in the recent uh in the past three years we see it's increasing more and more opposite of expectations if you wouldn't include these these aerosol changes and then uh so if you if you deduct the the amount of absorbed solar radiation if you deduct the outgoing heat radiation you get the net effect |
| 41:45 | and that's that's what you see here that there's a very high increase in how much net energy accumulates on Earth system which we call the Earth's energy imbalance and again this is this is from satellite data but it's um it's supported by evidence from Ocean heat content data and other evidence thank you Jeff you're on mute Leon thank you very much very clear and very striking uh let's turn quickly to Norman lobe uh at Nasa to talk about the satellite uh measurements uh and and |
| 42:26 | their Curren status uh and then we'll uh turn to Q&A there is so much M material here a number of people want to ask questions so let's see if we can squeeze in as many as possible okay can you hear me yes okay I'm going to talk about the the satellite measurements uh specifically series which stands for clouds and the Earth's radiant energy system um so we've seen different versions of this this is the series record uh Global meol Sky radiation I'm showing uh what we measure so we observe |
| 43:02 | the reflected solar radiation we have other instruments at Nasa that measure the incoming solar and so the incoming solar minus the reflected solar gives you the absorb solar and that's really what fuels the climate system in the blue it's the emitted thermal infrared radiation and that's essentially how Earth sheds heat and as we heard the differ between those two or the sum of these two um give you the net radiation and what I'm showing here are anomalies which are deviations uh from climatology and um the Striking thing |
| 43:40 | that we've observed with these measurements is this these Trends we're seeing a very large Trend as we heard in absorb solar radiation a weaker negative Trend in terms of more outgoing radiation um and so the net is a positive so so there's already a positive energy imbalance as I'm showing in the table below where it was about half a watt during the first 10 years of series and uh during the last 10 years leading up to um February 2023 it went to one watt so it's pretty alarming um and it's very robust because |
| 44:19 | we can compare it with uh insitu data from Ocean heat storage um this is the only record in the world uh the only dedicated record satellite record for Earth radiation in the world we're it um to put this into a different context you could take the green line I showed in the previous slide and integrate that over the whole globe and then look at the how much energy has been accumulated into the uh Earth system and um this is essentially it the monthly mean is in blue there's a seasonal cycle and then the 12- month |
| 44:59 | running average is in red and to put that into context the total energy that's been added to the climate System since we started taking serious measurements is 60 times greater than the global primary energy consumption so it's a lot of energy most of it as Jim said ends up as heat storage in the ocean about 2% is used to uh warm the atmosphere five to uh Heat land and the remainder is used to melt snow and ice and so the implications of this are are pretty huge for um for people living on Earth so here is the flight schedules we've |
| 45:41 | been really fortunate to have um been able to launch so many satellite instruments so there are six flight models of series uh two launched on Terra Satellite it launched in 2029 all of these are fiveyear nominal missions and truly remarkable um terara is still going 23 years later and we anticipate that it'll go uh through 2026 when it'll run out of fuel so it's really an engineering Marvel all of the instruments and satellite are doing great Aqua similarly I have two instruments there it's um just over 21 |
| 46:21 | years and will also uh run until 2026 we have two other series instruments flight models five and six that are flying on Noah satellites Sumi nppp launched in 2011 and Noah 20 in 2017 and those are doing great and could go um pretty far if they're allowed to but um there are programmatic constraints budgetary constraints that uh make their end life here uncertain and so we're hoping that these are allowed to continue and overlap with the next uh instrument that hasn't launched yet Libra instrument that's going to |
| 47:05 | launch um at the end of 2027 it's really important to have these overlap because a gap in the record would really increase the uncertainty um and so after Libra after its 5-year nominal Mission we have nothing planned at this point and so that means um first of all Libra could be a single point failure it could be the only satellite flying and um it'll be Beyond its Prime mission nine years from now and so that is concerning so at Nasa langly uh we've been developing uh Innovative small set technology uh that |
| 47:48 | can continue this record uh Beyond Libra at a much lower cost on a platform that is much more autonomous on a much smaller platform that's more Nimble in terms of launching uh than has been previously uh possible with these bigger satellites and so I hope we get the opportunity to to fly these uh satellites um to continue this very important record thank you Norman thank you very much uh very very important and very interesting we we'll turn to Q&A I I'd like to call set the born Ste of AP first and then Gloria dicki of |
| 48:29 | Reuters then Adam vaugh of times of London so Seth yes thank you um in term I have two questions U mostly for Dr Hansen uh when you re when I reached out to a whole bunch of other U mainstream climate scientists people like Z HOSA Michael man um the they said they called your work somewhat hyperbolic they said it is plaus on the edge of plausible or on the high end of plausible but not likely um and that might be fair to call some of the those some of the Kinder um and so in what is it but they also to be honest say you have a reput you know |
| 49:20 | your history is of of being right when you're out on a limb why are you right this time uh compared to other you know compared to the mainstream scientists and then the second question goes into the 20 the the 2.7 I mean 0.27 degrees per decade since 2010 um well that was started out as a strong El Nino year it also ended as a strong Lino year are you cherry-picking a start date here um I know Noah data shows it's 0. |
| 49:56 | 27 since 2010 um is that why chose why did you choose that date and and how does Eno factor in to you know when you're looking at that change and and that acceleration thank and thank you for doing this thank you Seth yeah okay to start with um how how do we get these conclusions and are they Fringe uh no you know it's very it's very simple uh the sensitivity is based on now very hard numbers the um for the temperature change between the glacial and interglacial times which for decades we thought that the claim |
| 50:49 | was that it was only 3 to 4° we now know that that's wrong and the uncertainty is small compared to the change so the physics there is very straightforward it's it's the real world that's telling us what the equilibrium climate sensitivity is and that's far better than models in which you can get any answer depending on what cloud feedbacks you put in uh but as George showed when you when you uh do improve your Cloud physics and make it look more like the real world it also increases the climate sensitivity |
| 51:34 | so there's every reason to believe that this is this is not Fringe this is the correct physics and it's the real world and it takes it sometimes takes the community a while to catch on uh now the other there was another thing about the physics what was the second part of that about the increased warming to 0. |
| 52:00 | 27 and the dates that you picked and and the evidence oh well that that was the third part but let me sorry sorry let me let me answer that third part uh no if you look at the uh temperature change since 1970 it's been basically uh was a straight line it's linear from 1970 up to the Past decade and the point that we're starting at I if if you saw the charts that uh Leon showed and um the change in the aerosols occurred from China and from the shipping uh beginning in about 2010 that's the reason to uh have that as the |
| 52:52 | hinge point and it's not at an stream at an elino or a lenino and we take the mean of that curve so there's no it's it's uh it is uh an objective way to do it and the other part and this may be what I was forgetting about the second part the physics is very clear the warming is due to the planetary energy imbalance you got more energy coming in than going out the planet warms up we've now got a doubled we've doubled the imbalance and that's going to increase the uh warming rate now it's |
| 53:39 | not simply based on the current imbalance you have to integrate over time and you're getting some still getting some warming from additions uh to the imbalance that occurred a 100 years ago but as we show quantitatively in the paper you'd still expect at least a 50% increase in the warming rate and that's what we will we will soon find out because you know the next few years will will show that indeed we do have an acceleration in the uh global warming rate thank you it's based on good physics you just look at the paper |
| 54:29 | you'll see that Jim thank you very much just to say we're a short of time uh there are a number of questions that have been uh asked on the chat and we will share those questions with the authors uh afterwards uh so uh some of you may get feedback by email uh but in the mean time let me ask Gloria dicki of Reuters to be next hi yeah thank you for doing this I just wanted to ask to kind of put this into the context of you know the global climate diplomacy and upcoming talks at cop 28 if 1. |
| 55:06 | 5 is indeed dead so much of the rhetoric of course is keeping 1.5 alive how do you kind of square that with what we're going to see in a few weeks I mean are you know world leaders kind of living in an imaginary world at this point you know what should the aims be of these talks uh how long do you expect it will take you know kind of policy and discussion to catch up to things that 1. |
| 55:28 | 5 is dead just kind of where do we go from here thank you yeah I think that is um that is a shortcoming of our scientific Community to not make clear to the political leaders what the situation is um 1.5 is De than adorning and anybody who want understands the physics knows that and it when you look at the real real the real potential if you look at the energy story you you will understand that you you are not the rest of the world is not going to suddenly get off of fossil fuels they're just too convenient they raise standards of living um as I said a |
| 56:28 | number of times one gallon of gasoline contains more than 400 hours of Labor by a healthy adult and uh and as I I showed a graph on the on the carbon intensity of energy we've we've reduced it from 08 to7 in 50 years it's not going to go to zero in a few decades and there are no plans to to do that and as uh pushkar's uh uh charts showed the assumptions that are made in these integrated assessment models that IPC is using are just inconsistent with the real world and what is happening so it it we're we're also going to pass |
| 57:20 | two degrees that's clear unless we take ctions to affect the planet's energy balance and and all those models by the way do not include the decreasing aerosols and the large additional burden that that puts you know one watt per meters squared is an enormous uh forcing to try to overcome I I it I I mentioned that if you want to do it by extracting CO2 it cost you more more than a hundred trillion dollar it's not going to happen so we have so young people need to understand what they are being handed |
| 58:05 | by the older generation they can't allow this fake uh stories to to mislead them they're going to actually have to affect the politics so that the special interests do not control and I the especially the fossil fuel industry does not control the future and in the United States you can't solve the problem with two political parties that are both taking money from the special interest I think that in in my opinion we're going to have to get a party that takes no money from special interests and that's the |
| 58:47 | only way we'll get policies that young people want and are needed to assure their future if I could could just add a word just to be absolutely clear uh the fact that 1.5° c is going to be exceeded must be interpreted properly to mean the emergency is much greater than these politicians either know or pretend it's not that it's less or that there's less reason for action there's much more reason for Action at a much more urgent pace and that's the real message of all of this so it it's not to |
| 59:31 | exonerate lazy politicians who have done little till now it's to tell them that uh their fakery is exposed because the rate of warming is higher the emissions continue to rise the drama that the planet is entering is much greater than they pretend and so the action has to be commensurate with that reality I just want to be absolutely clear that this isn't used to mock the idea of action it's the opposite it's to mock the inaction it's it's to say that the emergency is much much higher than |
| 1:00:11 | people realize right now and and I I just want to add add that point uh if we could turn to uh Adam vaugh of times of London hi thanks for doing this um James I just want has a couple of questions um are the five warmest months in a row that we've seen this year a sign of the acceleration you're talking about in your paper how worried would should we be by those temperatures um and I just wanted to ask just to get put your estimate on climate sensitivity in context a bit if you could do that um so you're saying 4.8 degrees for a doubling |
| 1:00:46 | of CO2 which is obviously a lot more than the ipcc I don't think it's and I'm obviously not a scientist I don't think it's completely out of line of other literature is it so I just wondered if you could just put it in context a little bit with what we've known before thank you I'm not sure I understood the question but the 4. |
| 1:01:09 | 8 degrees is actually not outside of the ipcc range they tend to give very large ranges but they said their best estimate was 3 degrees celius and it's is clear from The Real World response to the change in forcings between the glacial and interglacial periods the 3 degrees is excluded it's higher than that it could be the uncertainty 1. |
| 1:01:38 | 2 degrees would mean that 4 degrees Celsius is an is a possible sensitivity but even that is much larger than the 3 degrees now I Jim question yeah the first question was what should we make of the record breaking temperatures of of the recent five months is this part of the evidence of what you're arguing yeah absolutely it is if you look at the you know we part of the problem is separating signal from noise and you have a large natural variability of global temperature especially associated with the tropical uh Cycles the southern |
| 1:02:23 | oscillation but you can minimize that effect of that variability by looking at the peaks of the large El Nal and the most recent large El Nino was only uh eight or nine years ago and yet the warming since then it's already clear is going to be comparable to the warming that occurred between the prior super El ninos which was more like 18 years so the rate is is almost double and that's not surprising because the uh planet's energy imbalance is double so heat is pouring into the planet at twice the rate and that's that is a principal |
| 1:03:21 | reason why we're getting these extremely large month after month global temperatures thank you uh could we turn to Grist uh and if we have time we'll finish up with Alejandro deara at Time Magazine we're running late but let's uh try to get two more questions in hi um yeah my name is and if you could be quick please yes of course um I had a question about tipping points um which is you know what are the implic ations of those given um that your research shows will reach 1. |
| 1:04:01 | 5 by the end of the decade thank you yeah the the most important Tipping Point is the the Antarctic ice sheet and in particular the Thwaites uh Glacier which whose grounding line has been moving Inland at a rate of about a kilometer per year and in another uh 20 years it will reach a point where it it the the U bed uh is so-called uh retrograde bed so it gets deeper the Antarctic ice sheet sits on Bedrock below sea level but it gets deeper as you go toward the center of the continent and it get it hits a canyon in uh about 20 years if we |
| 1:05:03 | continue at one kilometer uh per year when it hits that Canyon you're going to get very rapid disintegration of that Glacier which is basically the cork that's holding uh a lot of the West Antarctic Ice uh in the bottle so we don't want to get there and if we want to prevent to slow down and even stop the melting of the Antarctic ice sheet we'll have to cool off the planet that's um and and we need to do that because more than half of the large Global cities in the world are on coastlines and there are a lot of |
| 1:05:47 | lowlands uh so that that's the Tipping Point which uh I think dominates but it so happens that there's so many other uh climate impacts that we're beginning to see and which would be much more if we go beyond two degrees that there are many reasons to want to cool off the planet if we want to keep a planet that looks more or less like the one that has existed the last 10,000 years we actually have to cool off the planet back to a hallene level temperature and that's possible but it's not easy |
| 1:06:25 | maybe if you could just to say one more sentence on that that is essentially Mr delara's question what do you mean by cooling off the planet I I mean cooling it back you know we it to comparable to what it was before the but but how is the is the question oh how well we we're going to have to reduce emissions as rapidly as practical because otherwise any artificial ways to cool the planet are going to be overwhelmed uh but we know when penut tuo went off it put aerosols in the stratosphere which re changed the planet's energy budget by |
| 1:07:10 | three watts per meter squared reduction if you had that now you know that cool that actually cools off the planet that's more than enough to put you from warming into cooling so there are there are ways to do it uh it and not just putting aerosols in the stratosphere there you can have uh autonomous sailboats putting uh sea salt in the atmosphere and seeding clouds which many people would consider more innocuous than putting aerosols in the stratosphere but rather than describe those efforts as threatening geoengineering we have to |
| 1:08:00 | recognize we're geoengineering the planet right now this what we're doing with these huge greenhouse gas amounts in the atmosphere is forcing the planet at a rate 10 times greater than has ever occurred in the Earth's history as far as we know we have to minimize that human-made geoengineering and on a temporary time scale that will probably require reflecting sunlight just because of how difficult it is to get the greenhouse gases out of the atmosphere now we're not going to do such a thing this year or next year people have to |
| 1:08:43 | understand the situation they have to see that the problem is getting worse and worse and and we have to understand the implications better but we should opposite I think that's that's important to to make clear that we're now doing the opposite of of uh reflecting more sunlight we're reflecting less sunlight yeah that's why it's become that's why the warming rate is in is accelerating because we're actually decreasing human-made aerosols um but when when you instead of we have to |
| 1:09:20 | compare the current geoengineering with the strong warming that that causes and all the problems that's going to cause at low uh latitudes and increased storms and increased uh floods and things with the situation where we we uh bring the temperature back down and it may have Regional effects but overall the global climate effects are are likely are surely much less than if we continue on this path and get several degrees of global warming uh yeah no I think we're going to have to close because we're 10 |
| 1:10:06 | minutes after the hour um I want to thank uh everybody for participating uh please everybody uh uh down make sure that you have the the paper uh it is an extraordinarily important uh paper um and we have a number of questions in chat which we will uh convey to the authors and I'm sure that uh the authors will also be ready to follow up with you directly uh by uh by email uh and if we could put a link uh Allison in the chat for people to follow up directly with you so that we can help to intermediate uh intermediate the |
| 1:10:53 | questions uh let me thank everybody again and uh uh we're in a in a grim situation I and I think that's clear uh it's even Grimmer that uh the politicians have failed uh their responsibility to the world now for quite a long time I for one am horrified to put them in a position of further engineering a uh a a a disaster when they can't even do the straightforward things but that's a that's a time for another another talk um and and another uh uh another discussion we we have a massive |
| 1:11:40 | political failure our politicians like Wars uh they don't want to save the planet in the right way so let's bring it to an end now and thanks uh Jim uh thank you uh uh George pushker Leon and Norman for a extremely important contribution to the scientific and to the public understanding and thanks to the colleagues uh uh at uh the UN sustainable development Solutions Network for arranging this uh conversation with the world leading climate scientists and best wishes to everybody today and byebye thank you |
| 1:12:21 | Jeff very much thank you thank Youk he |