World cities projected to go 4 degrees C hotter and beyond – scientist Lei Zhao. Dr. Robert Nicholls of UK Tyndall Centre finds official plan by world governments to green the planet with bio energy would create water stress for billions of people. Johannes Lohmann from the University of Copenhagen warns Earth will hit climate tipping points much sooner than expected due to the rate of climate change.

Buckle up for hair-raising triple science right here on Radio Ecoshock.

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



It takes a ton of work to produce a program with three interviews, two in both radio formats and YouTube plus this blog. This show took about 50 hours of work, spread over a month or so. If you can help me keep going, please do. One-time donations or monthly subscribers are the only source of income for this program. Nobody has to sign up, be bothered with email or advertising. Your generous donations make this essential information available to the world as freely as possible. Thank you.
– Alex



From the University of Copenhagen worrying new research about the speed of climate change. Johannes Lohmann is a Postdoc at Denmark’s famous Niels Bohr Institute. His five papers as a young scientist hunt for abrupt climate events in the past. Now he has news about grave risks in the future – how tipping points could arrive much sooner than predicted.

Listen to or download this 19 minute Radio Ecoshock interview with Johannes Lohmann in CD Quality or Lo-Fi


Or watch it on this YouTube video…


Do we know WHY the climate can remain in one state for many thousands, even millions of years, and then massively heat up in less than one human lifetime? Not really. But it sounds like a key goal to chase as humans destabilize the atmosphere with strange side-effects already arriving. To date science has offered us graphs of smoothly sloping lines upward – of carbon dioxide in the atmosphere, or heat and seas rising. We know those smooth figures represent the ups and downs during seasons and years. A look at climate during the ice ages show very dramatic spikes up and down in temperatures. Many are called “Dansgaard-Oeschger Events”.

All of Johannes’ five previous papers were about “abrupt glacial climate changes” and “Prediction of Dansgaard-Oeschger Events”. Those are known relatively rapid climate shifts appearing in Greenland ice cores and even dust. These climate events happened 25 times in the last glacial period. He was hunting the past for rapid climate change.

A lot of great science shows there can be “tipping points” or “critical thresholds” where some part of the Earth system moves quickly from one state to another. We try to estimate how much extra energy or other force it will take to reach that tipping point. For example, scientists gauge how much warming to expect from a doubling of carbon dioxide in the air (called Earth Climate Sensitivity).

But now in a new paper published in the top journal “Proceedings of the National Academy of Sciences, emerging scientist Johannes Lohmann finds a surprising factor in at least one case: meltwater required to slow or even stop the great circulation of the North Atlantic. It is known as “the Gulf Stream” or more technically as the Atlantic Meridional Overturning Circulation, or AMOC.

That current determines the climates of New England, Canada’s Maritime provinces, the UK, and most of Northern Europe. Without those warm waters from the tropics, all these places would be much colder, as their true latitude suggests. A number of recent studies show AMOC is slowing. Here is a great Twitter string from Radio Ecoshock guest Michael Mann on the AMOC slowing.

I will have more on the weakening ocean circulation in the North Atlantic in coming weeks. But actual changes to the climates of North America and Europe should be centuries away at the very least, given the amount of fresh water coming off Greenland. But Lohmann finds another shocking factor: changes in the environment do not depend merely on cumulative amounts, but can also be shifted by THE RATE of change.

The title of his new paper is: “Risk of tipping the overturning circulation due to increasing rates of ice melt”.

It seems likely this rate of change factor will apply broadly to many other cases. We know that is a factor in species going extinct. A slow warming may allow time for animals or plants to either evolve or migrate to cooler places. A high rate of warming can bring extinction.

Johannes Lohmann with Greenland ice core


This paper by Lohmann is actually his Doctoral Thesis for his PhD! I have never seen a Thesis published in the journal Nature. That is how important this is, and how exciting it is to see Lohmann emerge as a scientist. This is a challenge in a wide array of fields to find the impacts of rate of change. I wonder if climate models will also have to be adjusted because of this. Certainly our comforting expectations about the future have to be modified. This is more evidence humans simply do not realize the possible impacts of our civilization on nature. We are running a dangerous experiment… blindly.


We also get another example here of how the pandemic is holding back important science in climate change. Lohmann and colleagues were due to go to the Greenland glaciers this year to gather more samples. But like Antarctica, Greenland is out of bounds during the COVID crisis. There is so little medical care available there, and distances so great, for a tiny year-round population, that only a few are allowed to go there for essential maintenance. As with our interview with Antarctic explorer Sridhar Anandakrishnan, research on Greenland will likely be set back at least TWO years. That is two years when we have hardly any time left before we are committed to the worst of climate change. We did not have that time to lose.



Do we really know how far the ocean will move inland because of global warming? Did you know key cities are sinking faster than seas rise? We have more immediate threats like COVID variants. Listeners are losing their jobs. Who cares if the ocean is creeping up? It turns out this will change everything.

We return to the expert who advises governments, the Intergovernmental Panel on Climate Change, and multiple projects around the world. Robert J. Nicholls is Director of the UK’s Tyndall Centre for Climate Change Research and Chair of Climate Adaptation at the University of East Anglia.

Listen to or download this 27 minute Radio Ecoshock interview with Robert Nicholls in CD Quality or Lo-Fi


Or watch this interview on YouTube…


According to Columbia University’s Earth Institute by 2025 about 35% of humans will live within 60 miles of the coast. Why should the rest of people living inland stay tuned to our discussion of rising seas?

I’m reminded of flooding in Thailand in 2011. That sounds far away, but it turns out most of the factories making the world’s hard drives shut down. Western Digital lost 60% of production and said it would take more than a year to recover. We are all so tied together, and especially to areas in Asia prone to flooding. Nicholls talks about the shocking case of Tokyo and Jakarta, as sinking cities. From pumping out groundwater to expanding seas, none of this happens against a stable backdrop. Sea level is not stable, but neither is land level.

Tokyo is a classic case of groundwater sinking, dropping over 4 meters, more than 12 feet in a hundred years. About two million people live below sea level in Tokyo, dependent on sea control measures. Meanwhile the capital of Indonesia, Jakarta, is the fastest sinking city in the world, mainly because millions of people are drawing out groundwater for personal use and industry. The Government of Indonesia is talking about leaving Jakarta to establish a new capital city on the island of Borneo. Sea level of course is also rising on Jakarta, and this may be the poster-child for major cities having to abandon their site to the sea.

The new paper led by Nicholls is “A global analysis of subsidence, relative sea-level change and coastal flood exposure”. That was published March 8, 2021 in the prestigious journal Nature Climate Change.

In some places, including Portsmouth UK, the number of high sea level events has gone up, but actual flooding of the town has gone down. This is due to adaptation (portable water gates get installed with enough warning). This is an adaptation cushion which can hide real impacts, for a while, until overwhelmed. We see a similar situation with deaths during heat waves. After thousands die in a heat wave, governments react with cooling centers and other measures, and deaths go down. So increasing seas and heat can be hidden for a while by adaptation, but continue to grow as a threat. The false pause may create complacency and reduce spending to really adapt to major changes coming.

Realistically, I think we are all piddling away these critical years for climate action. Maybe it’s a King Canute situation. We cannot order the land or the sea to be stable. Now is the time to prepare and adapt.

CNN Coverage here,

and here is a Nova Scotia town sinking as seas rise



Heat and the Rising Sea

Heat and the Rising Sea
Posted on March 11, 2015, by Radio Ecoshock


Robert J. Nicholls, Adaption to Sea Level Rise, posted Oct 26, 2016.



If you live or work in a city we have news about your future. New research shows climate projections of 2 or 3 degrees C. warming are not for you. The trouble is: numbers you hear about warming are the global average. So that includes the oceans covering about 70% of the planet surface. More than half of all humans live in cities now and the United Nations projects that will go over two thirds by 2050.

Listen to or download this 12 minute Radio Ecoshock discussion about new science from Dr. Lei Zhao in CD Quality


Because cities only cover about 3% of Earth’s surface, they do not show up in global climate models. Now a team led by Dr. Lei Zhao zeroes in on what cities can really expect. He is the lead author of the new paper “Global multi-model projections of local urban climates”. That was published January 4th, 2021 in Nature Climate Change.

Dr. Lei Zhao is an Assistant Professor in the Department of Civil and Environmental Engineering at the University of Illinois. After graduating from Nanjing University, Lei got his Doctorate at Yale. He specializes in the physics and engineering of the atmosphere, with a focus on urban environments.

Dr. Lei Zhao, University of Illinois

It is fine to talk about the global mean temperature going up a degree or two or more , as we heat the planet. But cities get a lot hotter than the average, which includes vast areas of the ocean. How much difference is there between GLOBAL warming and what really happens in cities?

Lei Zhao tells us during this century the AVERAGE city temperature will rise 4 degrees C – 7 Fahrenheit – higher than year 1900 temperatures. Depending on geography, some cities will heat less than that, some much more, and all will get even hotter during heat waves. Many cities will heat beyond human endurance. It will be dangerous to be outside for long. City-dwellers will depend on air-conditioning and the energy required to run all that. That is already true in many cities around the world, but the heat is just getting started.

I have a 31 minute interview with Dr. Lei Zhao, currently at the Department of Civil and Environmental Engineering at the University of Illinois. After graduating from Nanjing University, Lei got his Doctorate at Yale. He specializes in the physics and engineering of the atmosphere, with a focus on urban environments. We don’t have time for the whole conversation this week, and some of you would find Dr. Zhao’s English second language a bit difficult. That is a growing problem now that so much great climate research is coming from Chinese educated scientists. We can’t ignore the kind of genius Dr. Zhao brings, and yet English listeners are not used to working our ears hard. We expect the voices of professional broadcasters to tell us everything.

To help get this important information out, I am posting the full interview with Lei Zhao here. It has not been fully edited.

Listen to or download the full 31 minute Radio Ecoshock interview with Lei Zhao in CD Quality or Lo-Fi


In the broadcast show I summarize our conversation and play a couple of clips, but it’s always best to listen to the source yourself.


Dr. Zhao’s team used innovative techniques to capture urban warming from a series of different climate models. Cross-checking with a “multi-model” approach increases confidence in the results. We know cities get much hotter than their surrounding country-sides.

Vegetation can cool the land – up to a point – by providing shade and transpiring water, a process the works like an evaporative cooler. By contrast, the materials used in cities absorb heat, like black asphalt roads and roofs. Vertical structures in cities block air transport that might have taken heat away. Then we add all kinds of heat in air-conditioner and vehicle exhaust. Cities are heat engines.

You have heard about the “urban heat island” effect and I have covered that on Radio Ecoshock with guests like Dr. Mat Santamouris, Eunice Lo, and Jane Baldwin.

Extreme Floods, City Heat & Politics

The End Is in Sight?

Abrupt Permafrost Thaw & Repetitive Heat Waves

In 2018 I interviewed Dr. Mattheos Santamouris in Australia about city heat. He measured temperatures of 158 degrees Fahrenheit, 70 degrees C on an upper level car park in Darwin. Some places in cities can be burn your skin hot.

…most humans will get much hotter than the 1.5 or 2 or 3 degrees C warming discussed by world scientists and governments

So most humans will get much hotter than the 1.5 or 2 or 3 degrees C warming discussed by world scientists and governments. I can’t stress this enough: most humans, most of you, will experience heat well beyond that. At times, Dr. Zhao tells us, cities will heat as much as 7 degrees C – that is 12 degrees Fahrenheit – hotter than the surrounding countryside which is already sizzling. Large-scale climate models simply can’t pick that up.

Dr. Zhao confirms, there is special concern for extra heat in cities during the night. Health studies have shown far more people die in heat waves when their bodies do not get a chance to cool down at night. Cities in this 21st century will be much hotter at night than previously. That also means more energy use at night and, with our current electric system, even more global warming gases from fossil-based power stations. No, those coal, oil, and gas power plants are not shutting down in the next few years. The hotter it gets, the more energy we use. Productivity also drops.

The Zhao study in Nature Climate Change finds one possible mitigating factor. Humidity goes down in cities during the heat. That is key because the combination of heat and humidity causes human death. The guideline is 35 degrees C. “wet bulb” temperature – a scale that measures when our bodies can no longer cool using sweat. But in our interview, Lei Zhao says the ever-increasing heat in cities will overwhelm the lesser humidity, returning to the danger zone.

The amount of new heat will vary from city to city, depending on many factors including geography. For example, their projections show cities in the East and Northern parts of China get significant warming. Multiple models show cities in the East and North China will undergo about 4 degrees C of warming this century! Zhao cites the study “Future temperature in southwest Asia projected to exceed a threshold for human adaptability”, published in Nature Climate Change in October 2015.

In South America, the urban hot zones to watch will be inland cities. But it’s everywhere. The authors say,

cities in the United States, Middle East, northern Central Asia, northeastern China and inland South America and Africa are estimated to experience substantial warming of more than 4 [degrees C] [K]— larger than regional warming — by the end of the century.

Zhao says studies of coming heat waves in cities are very alarming, going beyond safety range, beyond human adaptability.

As Dr. Santamouris told us, there is a lot we can do alleviate some of the heat. Greening up cities is crucial, with trees and plants of all kinds everywhere. Every other surface should be white, to reflect more of the sun’s energy back into space. We need to increase urban albedo levels. Of course more city infrastructure will go underground and homes with basements will increase in value. Skyscrapers in Toronto Canada use nearby lake water for cooling. Electric cars do not have a hot exhaust, while solar and wind power do not add more greenhouse gases when energy demand goes up in heat waves.

As with most diseases, the best cure is not to get it in the first place. Humanity needs to scramble into all-out emergency change to prevent the worst climate outcomes. Either that, or get ready to suffer through this century. Maybe we will all move back into caves.

If this show has stressed you out, go back to last week’s broadcast, “Coping with the Climate Crisis” with UK climate psychologist Ro Randall.

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

Coping With The Climate Crisis – Ro Randall