“Our Final Warning: Six Degrees of Climate Emergency” – new book with guest Mark Lynas. Was the frightening weather of summer 2020 partly due to shutting down our cars, ships, and planes? UK scientist Chris Smith with new findings and a doorway to save ourselves during these wrenching changes. Spot music “With Peace In Our Hearts” new from Eliza Gilkyson.

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Welcome back to a new season of Radio Ecoshock, as terrible 2020 unfolds. The 2020 summer climate was frightening. Northern Siberia, in the Arctic Circle experienced tropical temperatures. At the start of September, Arctic sea ice was near record lows. Japan went through a deadly heat wave while China struggled with massive river floods threatening the Three Gorges dam.

You know California and the whole Western United States were burning with record heat, drought, and horrifying wild fires. One of the hottest temperatures every recorded – 130 degrees Fahrenheit or 54 C was measured in California’s Death Valley. Hurricane activity is up with a double system slamming the American Gulf, including a Cat 4 and storm surges up to 20 feet high.


What will happen if Earth warms two degrees or even hotter? People turn to a key book by British author and climate activist Mark Lynas. In 2007 Mark published the book “Six Degrees: Our Future on a Hotter Planet”. The new update, with an incredible overview of the last thirteen years of science is out now: “Our Final Warning: Six Degrees of Climate Emergency”.

Author Mark Lynas

But there has been a lot of science since then, with more serious risks and warnings of climate catastrophe in the making. We need Mark Lynas to pour through masses of science papers, conferences, the whole fire hose of new information – and update the big picture. That is just what he has done. The new book now out is “Our Final Warning: Six Degrees of Climate Emergency”.

His 2007 book Six Degrees was a kind of definition arrived at by scanning the best science of the time. For over a decade, until now really, thousands of authors will repeat versions of Mark’s summary of impacts by degrees in all sorts of articles, books, and documentaries about climate change. Mark did the work and translated science into an almost movie-like vision. In fact, his book was made into a full length film by National Geographic in 2008.

As before, in the new book Mark turns each degree of warming into a Chapter of previews of the future – derived from science. I almost immediately skipped to the end chapter, to read about six degrees of warming. I did so not because I believe that is our inevitable future, but because I find it highly unlikely we will go extinct any time soon.

Strangely, Mark found there was practically nothing in the scientific literature about the course of life with six degrees of warming. That is the upper level ever considered by the Intergovernmental Panel on Climate Change (IPCC). While such a high level of warming is unlikely, it cannot be ruled out. Why have scientists left those pages blank? Perhaps they think humans, or organized humans, would not be around if such an extreme warming occurred.

In 2009 European scientists organized the “4 Degrees and Beyond International Climate Conference” at Oxford. Two years later there was a follow up conference in Australia “Four Degrees or More?”. But that seemed to be the end of it.

Ironically, a paper published in Nature August 26th revealed the coldest period of the ice ages was six degrees C. cooler than today’s average. Jessica Tierney from University of Arizona is the lead author. The press release says “Tierney and her team determined that for every doubling of atmospheric carbon, global temperature should increase by 3.4 C (6.1 F), which is in the middle of the range predicted by the latest generation of climate models (1.8 to 5.6 C).” end quote. Maybe we have been in the happy middle for the last ten thousand years.


Just recently the news reports that 2000-year-old redwoods survived California wildfires, including a 329 foot tall monster known as Mother of the Forest. In your book you write about times of mass extinctions when world forests burned, lighting up the night sky. Is it possible we have already reached a level of warming when forests can no longer survive in California?

About ten years ago, government scientists in British Columbia quietly predicted parts of Provincial forests would convert to grasslands due to climate change. That includes the forests around my own home, and sure enough we too have seen repeated wildfires in all recent years. Now we have reports that (a) fires in the Amazon are again threatening it’s future and (b) wildfires in over-heated Siberia have already released 35% more carbon than the total emitted from that region in all of 2019.


I worry the degree system of measuring global warming is misleading the public. Two degrees of warming does not sound like so much, if it means every day is just two degrees warmer than the same day in years past. But scientists are talking about a global mean average temperature rise of two degrees, including the giant pool of the ocean. Temperature changes on land will be much hotter, with a lot more variation, meaning more extreme weather. Is this official degree system understating reality?


Although a few bleak voices suggest we will reach 5 degrees of warming by the end of this century, the majority of scientists I interview do not think that. Many still talk as though two degrees is a realistic target. Another large group sadly suggest the most realistic outcome is 3 degrees of warming, by 2100 or perhaps 2150. Mark what do you see as the majority view among climate scientists?

If we take three degrees of warming within 100 years as the most likely outcome, here are a few examples from the new book by Mark Lynas. The last time Earth was three degrees hotter than pre-industrial times was a period called the Pliocene over 3 million years ago.

The ice was very different in that hotter world, Lynas writes:

All that water – from the absent West Antarctic Ice Sheet, the tiny rump of Greenland, and the much-reduced East Antarctic Ice Sheet – had to go somewhere, and as a result of this colossal outpouring of meltwater, sea levels during the Pliocene were as high as 22 metres above where they are today.

In first Six Degrees book, Lynas estimate the collapse of the West Antarctic ice sheet would happen at 4 degrees C. of global mean warming. Now with a barrage of recent science, that giant melting may begin at 2 degrees, and much higher sea levels are expected with three degrees of warming. But there is a delay factor in ice melt that could take several centuries before sea level found a new higher balance. With our greenhouse gas emissions, we are changing the coast lines for centuries to come.

Plus, as Mark puts it, the new three degree climate will be “Hotter Than Hell”.

The extreme heat of 2019 will be considered an unusually cool summer in the three-degree world. Vast regions of South Asia are projected to experience heatwave episodes ‘considered extremely dangerous for most humans’ in a world that is just 2.25°C warmer than pre-industrial times. A heatwave so extreme that it might currently be expected only four times a century will become not just a regular occurrence, but take place every other year. The projections show that over half of South Asia’s population – hundreds of millions of people living in dozens of major cities – will be experiencing ‘dangerous heatwave’ conditions never before seen in today’s climate.

Do you want to see this future? Mark spends a well-documented and well-written chapter exploring the world at three degrees and higher. This book will now become the reference used by journalists, politicians trying to understand, students, and all of us. Reading it is the education we all need.

We tend to get strangely excited about total doom. People make movies about it, and the Bible describes the End Times. I think a more realistic and near-term problem is this: at what level of warming does civilization collapse to a point where no organized effort can be mounted to save a livable climate. At what point do we become helpless witnesses on the road to Hell?

Follow the work of Mark Lynas at his web site.

Mark previously appeared on Radio Ecoshock on January 28, 2007.

Mark Lynas: Six Degrees of Climate Change



Various citizen scientists feared sudden heat if the layer of cooling smog disappeared. But what could stop industrial civilization and all those cars, planes, and ships? We found out with the COVID-19 pandemic. But was the strange weather in the Northern Hemisphere really related to the shutdown, or is this just the new UN-normal as we force Earth into a hotter state with everyday emissions? A world expert will answer those questions and more.

When the pandemic stuck the world in 2020, business, travel and institutions shut down to limit the spread. That meant a sudden reduction in global warming gases many thought impossible. But was it enough to derail the developing climate nightmare? “Not really” says a new study from UK and European Union scientists – but how we manage to recover could either speed up or delay the great warming. Do we go back to normal – or change toward lower emissions?

Our guest is uniquely qualified to answer this puzzle. Dr. Chris Smith is a Research Fellow for the Institute for Climate and Atmospheric Science at the University of Leeds. Chris is also deeply involved in a project called the Constrain Consortium – to investigate primary climate unknowns ahead of the next international climate meetings, whenever those may be.

Dr. Chris Smith, University of Leeds

Chris is co-author on the new paper in Nature Climate Change “Current and future global climate impacts resulting from COVID-19”. COVID and climate are like big game changers that interact.

In a graphic for the paper, we see a dramatic cliff fall in a range of climate changing gases in March 2020. But the most dramatic are for lesser drivers like black carbon and various nitrogen compounds. The really big players – carbon dioxide and methane – do not drop anywhere near as fast or as far. This tells us that the smog from car exhaust and planes went down, but we kept large carbon emitters like power plants running full tilt.

If I read this paper correctly, it sounds like the biggest greenhouse gas impact we could hope for from the shutdown might be around 2 parts per million less greenhouse gases than expected, in a couple of years. Global CO2 levels have been increasing by around 3 parts per million in recent years.

This new paper in Nature Climate Change suggests the real change to watch for could be local appearances of extreme weather. That made me think of the unnatural rains in China recently, and the blistering record heat in the American Southwest. Some worried that a COVID shutdown could bring a rapid warming, once the cooling layer of pollution dropped to reveal full sun power. This event was too close to us in time for science to give us definitive answers on what the shutdown brought.

It surprised me to find in the paper that whether we come back with dirty emissions or a green path, it won’t really make any difference until at least 2030. There is a big delay, and that could make any sacrifices for a green re-growth a harder sell, because we will not see an immediate payoff.

I take issue with one assumption in the recent Nature paper. The authors assume the disease interruption to emissions is just temporary. What about (1) a more permanent move away from commuting every day to home office workers and online business (a lasting impact); (2) greater unemployment meaning less mobility, both for work and leisure travel? What if we don’t come back, and in fact fall into a deeper Depression where nobody can afford to go anywhere or buy much of anything. Isn’t it possible that a prolonged economic collapse really could make a dent in our race to heat the planet?

This new study concludes:

we estimate that the direct effect of the pandemic-driven response will be negligible, with a cooling of around 0.01 ± 0.005 °C by 2030 compared to a baseline scenario that follows current national policies. In contrast, with an economic recovery tilted towards green stimulus and reductions in fossil fuel investments, it is possible to avoid future warming of 0.3 °C by 2050.


Le Quéré, C. et al. Temporary reduction in daily global CO2 emissions during the COVID-19 forced confinement. Nat. Clim. Change 10, 647–653 (2020).


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I’m Alex Smith. Thank you for listening, and for caring about our world.