What is behind the strange burst of heat around the world and crazy weather? Hear best answers from a half dozen experts including: Michael Mann, James Hansen, Gavin Schmidt, David Victor, Leon Simons, George Tselioudis, and YangYang Xu.

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

 

It’s been record heat in Texas again, well over 100 degrees F, 38 C, a month early. The Texas utility ERCOT set a new May record of 78,000 megawatts of power consumed, with AC working overtime. The heat went right up into Canada, with Winnipeg beating any May temperature in 137 years.

According to Meteorologist Bryce Anderson “The Arctic had its second-warmest January-April period on record, with a temperature 3.68 degrees C (6.62 F) higher than the 20th-century average….across much of the Arctic Ocean, Asia, Alaska, northern Canada, and northern Europe, temperatures were at least 2.5 degrees C (4.5 F) higher than the 1991-2020 average.“

Countries across North Africa to the Middle East were stupidly hot. High temperatures ranged from 47C (116 F) to more than 50C (122 F) setting new records for May. It is too hot for humans outside, and a lot of animals too. This is a new climate state much hotter than the 1900’s.

With early summer heat in India and Pakistan, temperatures rose above 40 C (104 F) and, in some locations, were as high as 49 C (120.2 F). Thailand reached a record-breaking 42.3 C (108.1 F) in April. So far, we are experiencing the second hottest Spring ever, just behind 2024. Are we stuck in climate acceleration?

The World Meteorological Organization just updated their heat predictions to 2030. Now they find a good chance we will be above 1.5 degrees C globally hotter by that time, and Earth could experience a couple of years as hot as 2 degrees C over pre-industrial. The public does not know what is coming.

THE LATEST FROM MICHAEL MANN

Before we dive into what’s behind the latest burst of world-wide heat, you should hear this short speech by Michael Mann. He delivers the keynote talk for Graduation at the University of Pennsylvania. It was streamed live on May 16, 2025.

 

 

Michael emphasizes the need for science in society, and why these graduating students, including scientists and health specialists will be badly needed in the future we are making. It is a great clear speech worth your time.

LATEST FROM JAMES HANSEN

Now on with James Hansen and acceleration. James Hansen has a new warning about escalating heat. Earth has become less reflective, sending less light back into space, leaving more energy in ocean, land and air. Extra solar energy expresses itself as more extreme heat, changed ocean currents, and potential for violent weather – all happening now.

On May 13 James Hansen and Pushker Kharecha published an article titled “Large Cloud Feedback Confirms High Climate Sensitivity”. Don’t let the title fool you. As Hansen and Kharecha say, this is a big fucking deal, BFD. They say Earth’s albedo has decreased by about 0.5% since the early 2000s. That sounds small but it represents vast amounts of solar energy staying in the Earth system, energy greater than we can imagine. It translates to roughly .5 Watts per Square meter, adding as much as half a degree to the global average mean temperature. That is a BFD. Hansen’s new paper suggests the extra energy is like adding 138 parts per million more carbon dioxide to the atmosphere.

NASA’s CERES satellite data and measurements of “Earthshine” – reflected sunlight observed from the Moon – back up Hansen’s .5 % decline in this planet’s reflected energy. This is not a theory. But the cause is still debated by scientists. Michael Mann made respectful but pointed critiques of Hansen’s recent papers, especially regarding claims of rapid acceleration in global warming and the outsized role of aerosols. Mann argues that Hansen’s conclusions overstate the case and are not well-supported by the evidence, stating, “the truth is bad enough without [what he sees as] alarming exaggeration.”

Hansen and his co-author conclude:

“Earth’s darkening, by itself, provides strong proof that climate sensitivity is much higher than IPCC’s best estimate of 3°C for doubled CO2.”

They think the doubling, likely before year 2100, leads to about 4.5 degrees C. of warming. That is disaster.

In the program you hear a short clip released by James Hansen in February of this year, along with co-author Pushker Kharecha , to accompany their related paper “Global Warming Has Accelerated: Are the United Nations and the Public Well-Informed?”.

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TRANSCRIPT – HANSEN AND KHARECHA

[Video transcript]

“Jim: I’m Jim Hansen. Pushker Kharecha and I will discuss a new paper that explains the global temperature spike in the last 2 years. A tropical El Nino spurred it, but only explains part of the warming.

Pushker: The other part is caused mostly by reduction of aerosols produced by ships. Aerosols are tiny particles that serve as cloud formation nuclei. They increase the extent and brightness of clouds, which reflect sunlight and cool Earth’s surface. When clouds are reduced, Earth becomes darker – absorbs more sunlight – which causes warming. Ships are the main aerosol source in the North Pacific and North Atlantic.

We use satellite measurements to estimate that ship aerosol reductions caused almost one-third of global darkening. Reduced snow and ice account for one-tenth. Thus, most darkening must be cloud feedback – warming-induced cloud reduction.

Jim: Large cloud feedback implies high climate sensitivity. Ocean temperature will not fall even as the tropics cool. Ocean hotspots and other extremes will grow.

Warmer air fuels stronger storms, more extreme rainfall and floods, but also flash droughts and more extreme fires. We could adapt to those and minimize damage, but there’s a bigger issue: the inter-generational effect caused by climate’s delayed response. We find that present polices are likely to cause shutdown of the ocean “conveyor” circulation within 20-to-30 years, consistent with evidence presented recently by the Ditlevsens.

Ocean conveyor shutdown would keep ocean heat in the Southern Hemisphere, speed up Antarctic ice melt, and raise sea level – eventually taking out coastal cities, Florida, Netherlands, Bangladesh, part of China.

That’s no reason for unhelpful alarm. Instead, we must clarify what is needed to produce a better future. Please read the Epilogue in our paper – no technical science, just a message for young people and all people. Thank you.”

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The new May post from Hansen and Pushker begins:

Earth’s albedo (reflectivity) declined over the 25 years of precise satellite data, with the decline so large that this change must be mainly reduced reflection of sunlight by clouds.

Essentially, Earth is more sensitive to greenhouse gases in the atmosphere than we knew. The full effect of our emissions has been hidden by clouds and pollution (which affects cloud formation).

SO MUCH HEAT, SO FAST

This is all part of the scramble by top world scientists to answer a dangerous puzzle: why was 2023 so much hotter, despite a weak El Nino? Why did Canada burn? Why were heat records set around the world? In April 2024 I asked Dr. Gavin Schmidt, Director of the Goddard Institute for Space Studies at NASA – James Hansen’s old job. The program contains a short clip from that interview.

Related to acceleration of warming, you should hear Professor David Victor. He delivers a stiff warning in the prestigious journal Nature: “Global warming will happen faster than we think”. His stellar co-authors are Yangyang Xu and Veerabhadran Ramanathan, both previous Ecoshock guests.

Dr. David Victor

There are really two factors at work in this acceleration of warming in the last couple of years. The first is human-caused pollution reflecting sunlight and stimulating cloud formation. The second is large system change to cloud formation directly due to global warming. Some of this discussion, and Hansen’s recent work, was stimulated by observation from a non-scientist, Leon Simons in the Netherlands. You hear it from Simons, on Radio Ecoshock January 11th, 2023.

Leon Simons

By the way, according to Atmospheric Scientist Chris Wright there was another surprising change when ship pollution rapidly dropped. In March 2025, Chris wrote: “lightning over shipping lanes dropped by half almost overnight after the regulations went into effect”.

Did Leon Simons attribute too much to ship emissions, as “the” cause of excess warming since 2020? A number of leading scientists think larger natural systems are likely more important. We hear about both in this sample from my interview with George Tselioudis.

Dr. George Tselioudis

George Tselioudis is a Research Physical Scientist at the NASA Goddard Institute for Space Studies. Dr. Tselioudis came through physics to meteorology and entered the early days of climate science. Crunching 40 years of satellite records, George recently led a team analyzing cloud cover on Earth. They found the world’s storm-cloud zones are contracting. The land and sea are getting less shade, leading to record heating. This is breaking knowledge.

The paper is: “Contraction of the World’s Storm-cloud Zones the Primary Contributor to the Recent Increase in Cloud Radiative Warming”

I found a Preprint here.

COOLING SMOG

Ships are not the only factor in human pollution. Large parts of North India have been covered for months by dense smog. It has been unsafe to breath outside in the Indian capital of Delhi. A couple of decades ago, Ram Ramanathan of Scripps documented this long lasting cloud of pollution, calling it the Asian Brown Cloud. A similar bank of persistent smog formed over China during it’s rapid industrialization. Both China and India burn a lot of coal, which releases sulfates that reflect sunlight well. India in particular has been artificially cooled by pollution.

Climate Hope and Horror

 

Naturally, billions of people call for better air. Both governments are working to reduce pollution. China has been more successful so far. Part of that is their choice for clean renewable energy. It is said that China installed more solar panels in 2024 than the total for the whole world previously. About a quarter of all cars sold in China are electric, and heavy diesel trucks are next for conversion.

As both China and India clean up the air, there will be less sunlight reflected back into space, and less cloud cover for shade. We all will heat up even more. Cleaning up deadly air pollution does not add to global warming. It reveals the true power of the warming gases we have already released.

Our guest YangYang Xu gave us a clear explanation of this double-edged sword.

Global Heat Alert?

 

NOW IT GETS HARDER

YangYang has a powerful message. Cleaning up pollution is necessary. It can save millions of lives. But reducing air pollution DURING global warming means we need to do more to get less. It works, but not as fast as we might expect.

I think this is true of the whole greenhouse gas overload. Already entrained in serious impacts, from heat to destabilized weather and fires, we need to slash carbon emissions much faster. We will get less relief, than if we’d done it ten or twenty years ago. The deeper we get into climate change, the harder it becomes to save what we can. But there is no other choice.

I’m Alex Smith. Thank you for hanging in there, and still caring about our world.

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