Latest science with grim news: without action, Earth could warm 7 degrees C by the year 2100. French Senior Scientist Olivier Boucher explains. Rising seas are a sure thing now. Will we retreat in panic or plan our way out? Interview with expert Dr. A.R. Siders.

Listen to or download this Radio Ecoshock show in CD Quality (57 MB) or Lo-Fi (14 MB)


The latest models of Earth’s future reveal a terrible truth. French researchers at the top national research agency now say the path of this civilization could lead to a catastrophic warming of 7 degrees C. by the year 2100. This is devastating news. Previously, scientists suggested the limits of humanity begin at 4 degrees C. So now we know the stakes. It is literally change or die. The Earth will warm in this decade, and coming decades. We will experience more floods, fires, extreme heat waves, crop damage, storms more severe than seen before, insect invasions, species loss, changes in plants, – everything. But there is still time, these scientist find, to avoid the very worst, to rebel against extinction.

We are lucky to be joined by the Senior Researcher for the French team that last week released the results of the very latest generation of climate models. Dr. Olivier Boucher is Senior Research Scientist at Centre national de la recherche scientifique, the The French National Center for Scientific Research, the largest science agency in France. Olivier is head of the Institute Pierre Simon Laplace Climate Modelling Centre in Paris, part of the French group releasing the new results.

Dr. Olivier Boucher

Listen to or download this 25 minute interview with Olivier Boucher in CD Quality or Lo-Fi



Despite the blaring headlines, we are not predetermined or doomed to heat up 7 degrees C by the year 2100. The latest models (CMIP6) considered a range of possibilities, from 2 degrees C oF warming to the worst case. It’s just that the worst case is worse than we knew before. It could get to 7 degrees C by 2100, at least one degree above the IPCC previous top projection.

To get to that certain extinction point, humanity would have to ignore all the climate-driven disasters that develop during the next decades, to drop everything about the Paris climate accords of 2015, to ignore the dropping price of renewable energy – in short, we would have to actively do everything possible to commit climate suicide. You may think bleakly enough to accept that is our fate. but vast crowds of humans turned out just last Friday September 20 saying they DO want a future. We will go through hard, terrible times as the climate shifts. But there is still time to rebel against extinction. Find that growing global movement at The next international rebellion is set for October 7th.

An article about this study in VICE says:

In addition to global climate patterns, the new research zeroes in on some more local phenomenon (such as heat waves and tropical storms), simulating them more realistically than ever before.”

I have long thought that large local or regional events, like the Russian heat wave of 2010, or the Indonesian peat fires of 1997/98, can stimulate the whole process or timing of global warming. Could these shorter-lived events stimulate other processes, like thawing of permafrost, that speed up with a burst of heat? It sounds like finally the new models including “local phenomenon”, even hurricanes.

After all, the past couple of years has shown us a string of big events and instability, including major wildfires on every continent except Antarctica, extreme heat in Europe, and Category 5 hurricanes. Surely we cannot get an accurate model of developments on Earth without including instability and violent events.

VICE author Madeline Gregory continues:

The impacts of the worst-case scenario under the new models (a 7 degree Celsius warming by 2100) are severe, and will likely require more research to accurately predict. But it is estimated that, at about half of that warming, most species would not survive and all summer Arctic ice would disappear.


In this interview we also explore one of Olivier’s other specialties: the role of particles in the air, aerosols. Is better handling of aerosols in Earth System Models a factor in the newly released results of a much higher than expected temperature by 2100? Olivier says the real drivers are greenhouse gases, particularly carbon dioxide, and not aerosols.

There is a debate about how much heat aerosols are covering up. That is, if aerosol pollution was cleaned up to it’s pre-industrial state, but with the greenhouse gases we have up there now, how much higher would the global mean temperature be? Olivier has said elsewhere (Google translation from French):

Aerosol emissions have varied regionally over the last two decades: decreases in industrialized countries, due to policies to improve air quality, and increases in developing countries. Therefore, it is unclear whether aerosols have recently warmed or cooled the climate. It is likely that anthropogenic aerosol emissions will ultimately decline on a global scale. We can then expect a warming that will accelerate.”

But the warming from the arrival of more sun to the surface would not happen immediately, due to ocean buffering. More on that below.


If we warm very fast, as now looks likely, humans will be desperate for cooling solutions. In March 2019, Dr. Boucher presented a seminar called “Solar radiation management: global or regional?” Can we try to mount solar radiation management just over the Arctic, in order to preserve the last of the sea ice and slow down permafrost thaw? That is what Ottawa scientist Paul Beckwith has called for. Or do atmospheric currents take whatever we put up there and spread them much farther? Boucher says it is not possible to just cool one region using techniques like spraying sulfates into the upper atmosphere to reflect some sunlight back into space. The aerosols would spread out over the globe over time, with unknown results.

We know aerosols are a factor in changing precipitation as well as climate change. One of the fears about geoengineering – like solar radiation management, is creating inadvertent changes to rainfall. Is that a legitimate concern? In the interview, Olivier explains this risk, which is real.

Given latest model results showing a possibly unsurvivable future, while greenhouse gas emissions grew last year rather than shrinking, is it possible civilization will not survive without geoengineering? What do you think?


We have so much to learn from that interview with Olivier Boucher, a leading scientist in France. Suppose an economic crash, a terrorist cyber-attack or some other factor brought industrial society to a stand-still, even for a month or two. How long would it take for aerosols to disappear from the atmosphere, leading to a possible jump in warming? Olivier says the human-made aerosols could be washed out of the atmosphere in a matter of days.

It sounds like we can worry less about aerosols settling out of the sky causing an immediate jump in warming. Olivier Boucher says there would NOT be a sudden jump, because any warming unmasked would unfold over decades due to the large buffer we have in the oceans. The extra heating would arrive but it might take years or longer.

Even so, I will continue to follow the global dimming story, in part because that warming, somewhere between half and one degree C, is not counted when experts predict hot how the planet will get. But it is there. And we know that even a half degree warming can make a significant difference, as the recent report from the Intergovernmental Panel on Climate Change showed when assessing the differences between 1.5 and 2 degrees C. of warming. I have another interview on aerosol masking of global warming coming up soon.

From the Boucher interview, we also learn that the IPCC is switching away from the somewhat fake starting point of warming since 2010, to true pre-industrial warming, like what the air is thought to have been in 1750. We can’t lie to ourselves by moving the benchmark closer to the present. The new models run by the French agencies assumed a greenhouse gas baseline truly pre-industrial, which gives me more confidence in their results.



Sea level rise is baked into the cake now. Greenland and Antarctica are melting, as are all other land glaciers. We are committed to a world where ports and port cities become swamped, delta farmlands become invaded by salty water, and maps of the coastlines have to be updated every ten years. Will we wait until the next storm surge wipes out homes and infrastructure? Will we dumbly try to rebuild everything while pretending sea level rise is not real? Will we wait to panic – or plan a retreat that makes sense?

Coming up, the first in a two-part series called “Retreat from the Sea”.

Listen to or download this 27 minute interview with A.R. Siders in CD Quality or Lo-Fi


From Staten Island to Papua New Guinea – and now in the Bahamas – climate change forces people to retreat from the storm-tossed rising sea. “Retreat” means “defeat” – or does it? It turns out planned retreat is an emerging field of study, policy, and current events.

We are joined by a known expert in the field, Dr. A.R. Siders. She has a law degree from Harvard University and a doctorate from Stanford. Anne Siders worked on recovery in New York and New Jersey after Hurricane Sandy in 2012. She just joined the faculty at University of Delaware, working with the Disaster Research Center.

Dr. A.R. Siders

Her latest paper, published in the journal Science, is “The Case for Strategic and Managed Climate Retreat: Why, where, when, and how should communities relocate?“. The full paper is here.

I think it is worth passing on this summary of the recent work by A.R. Siders:

Faced with global warming, rising sea levels, and the climate-related extremes they intensify, the question is no longer whether some communities will retreat – moving people and assets out of harm’s way – but why, where, when, and how they will retreat. To the extent that retreat is already happening, it is typically ad hoc and focused on risk reduction in isolation from broader societal goals.

It is also frequently inequitable and often ignores the communities left behind or those receiving people who retreat.

Retreat has been seen largely as a last resort, a failure to adapt, or a one-time emergency action; thus, little research has focused on retreat, leaving practitioners with little guidance. Such a narrow conception of retreat has limited decision-makers’ perception of the tools available and stilted innovation.

We propose a reconceptualization of retreat as a suite of adaptation options that are both strategic and managed. Strategy integrates retreat into long-term development goals and identifies why retreat should occur and, in doing so, influences where and when. Management addresses how retreat is executed. By reconceptualizing retreat as a set of tools used to achieve societal goals, communities and nations gain additional adaptation options and a better chance of choosing the actions most likely to help their communities thrive.”

See also this article “The case for retreat in the battle against climate change” published August 22, 2019 as a news release from the University of Delaware. And check out this research article published May 1, 2016 “The Case for Retreat” by Liz Koslov in “Public Culture”. That article documents the buy-out programs announced by New York Governor Cuomo after Hurricane Sandy.

Liz Koslov writes:

Retreat is distinct from other kinds of climate-related migration in that it entails not just relocating a group of people but also unbuilding land and returning it to nature in perpetuity.”

Bangladesh has a policy for internal displacement, called “The Peninsula Principles“.

In the interview, we also discuss the case of Kivalina Alaska, which had to retreat from crumbling houses and infrastructure, largely driven by climate change. They sued Exxon-Mobil as major providers of those greenhouse gases through fossil fuels. But he Courts rules the Alaskan natives had no standing to sue. The possibility that big oil companies could be sued for climate damages was not resolves (it never got that far in court). So that is still a possibility in the future. See this paper by our guest: Siders Anne. 2012. “Ninth Circuit Affirms Dismissal in Kivalina v Exxon-Mobil.” Climate Law Blog, September 26.

The popular press is waking up to this growing need to move away from the coast. But big real estate developers, all the folks invested in seaside property, and the banks holding those mortgages are hoping you don’t find out too much. When Hurricane Sandy wiped out communities in Staten Island, residents organized “buyout groups”. But politicians from New York – like State Senator Chuck Schumer and then mayor Micheal Bloomberg – were against it. Schumer said the drive to rebuild on those exposed shorelines “shows the spirit of New York”.

Personally, I am pessimistic about governments and the public getting behind action before communities are wiped out. These days government don’t get much done even after those disasters. Isn’t it just as possible that victims of storms and sea flooding will just migrate without much help, as a lot of former New Orleans resident did after Hurricane Katrina?



We began this program staring down the barrel of possible extinction-level heating on Earth by the end of this century. That assumes the worst about humanity, and that we manage to keep converting fossil fuels into greenhouse gases. But on Friday 20th, there were a lot of other voices heard. I’m told that the largest public protest every held in Australia showed up to protest inaction on climate change. Young people demanded to have a future.

I have given Australia a hard time, if only because that country gets lots of signals with extreme heat, coral die-off, and bushfires. Despite going under the climate hammer, enough people vote for climate deniers to form government after government. Those politicians run on a platform of exporting even more natural gas, and even more climate-killing coal. Australia is already the world’s largest exporter of both these fossil fuels. Now a lot of Australians say that coal lobby does not speak for them. They want climate action.

As you know, there were a lot of climate protests, strikes and actions all over the world that day. None of that reduces our emissions on Friday. But it may be the start, the first step toward mass demand for a sustainable economy and a climate that is livable, or at least survivable. The people who stepped up are a breath of hope. Now we need to keep on working to change the ways we live. Life: it is a limited time offer – not just for each of us – but for our descendants as well.

As Jim Jefferies says, “We can all do better“.

I’m Alex Smith. Please help support this listener-funded program. Radio stations do not pay for the program and I make it available free to people all over the world. That means server bills, and other costs. Find out how to help here.

Thank you for listening to Radio Ecoshock this week, and for caring about our world.