Professor James Hansen believes the inadequate policies agreed at November’s UN climate change summit will lead to the planet breaching its 1.5°C danger zone this decade

In just a few decades, the Government’s inadequate pledges at the COP26 climate conference will lead to a rise in global average temperatures of 2°C, leading to the destruction of hundreds of coastal cities while shutting down the Atlantic ocean circulation system which regulates climate stability. 

This shocking analysis comes from Professor James Hansen, the first scientist to sound the alarm on global warming. Within this decade, he claims, the planet will breach the 1.5°C danger zone, putting paid to the triumphant claims of British officials in the wake of the UN summit in November.

Prof Hansen, a former director of the NASA Goddard Institute for Space Studies who heads up the Programme on Climate Science, Awareness and Solutions at Columbia University’s Earth Institute, is renowned for having published the first model-based warning of climate change back in 1981.

In a memo published last December – unreported until now – Prof Hansen warned that world governments and the UN’s Intergovernmental Panel on Climate Change (IPCC) are severely under-estimating the speed and impact of global warming this century. 

Conventional climate models, he said, do not sufficiently account for the Earth’s paleoclimate history or ongoing observations of the climate system. 


Overshooting 1.5C this Decade

Prof Hansen criticised Boris Johnson’s “claim that COP26 salvaged the chance to keep global warming below 1.5°C” and that “we’ll look back at COP26 as the moment humanity finally got real about climate change”.

Describing the UK Government’s claims about the success of the COP26 as “unadulterated bulls**t”, his memo warned that “the 1.5°C global warming ceiling will be breached this decade” and that pledges made by Johnson’s administration at COP26 will do nothing to stop the world hitting dangerous climate change, his analysis showed.

The academic argues that, within the next six months, there will be a rise in the 12-month running-mean temperature due to the El Nino cycle, which will “be accelerated by Earth’s largest energy imbalance in the past half century”.

By the second half of the 2020s, a further 0.1C will be added due to increased solar irradiance. The combined effect means that “there is now no chance whatever of keeping global warming below 1.5°C,” he says. 

Prof Hansen has also criticised COP26 President Alok Sharma who, after the summit in Glasgow, said “we can say with credibility that we have kept 1.5°C degrees within reach, but its pulse is weak”.

“Where did Sharma derive his claim of credibility?” Prof Hansen asks.


Two Degrees is Coming – And Will Lay Waste to Coastal Cities

Prof Hansen argued that, if fossil fuel extraction continues at the current rate, dangerous global warming will continue over the next three decades – resulting in a rise of 2°C, the upper threshold to avoid a climate danger zone. 

Based on current commitments at COP26, he sees little prospect that this trajectory is going to change, making 2°C all but inevitable.

“Global warming of at least 2°C is now baked into Earth’s future,” wrote Hansen in the memo co-authored with Earth Institute climate scientists Dr Makiko Sato and Dr Pushker A Karecha. “That level of warmth will occur by mid-century.”

If Prof Hansen is correct, this means that within the next few decades the planet will become warmer than the Eemian period – an interglacial period that lasted from about 130,000 to 115,000 years ago. This was the most recent time the Earth was warmer than it has been during the Holocene. 

The Holocene is recognised by scientists as a kind of ‘Goldilocks’ period for the climate – neither too hot nor too cold – and ideal for a habitable planet. The further we move away from these conditions, the more uninhabitable the planet becomes.

Prof Hansen argues that a rapid crash into the 2°C climate danger zone will happen because of the continued “failure of the world to develop a clean energy system for electricity”, as well as ongoing reluctance to invest in the expensive technologies to withdraw dangerous quantities of greenhouse gases out of the atmosphere.


The Catastrophic Consequences of 2°C

The academic’s memo highlighted two specific consequences of breaching the climate danger threshold which would have catastrophic impacts: rapid, exponential sea level rise; and the shut-down of the global ocean circulation current known as the Gulf stream. 

A sea level rise of several metres would mean the “loss of most coastal cities and is irreversible on any time scale that people care about,” he says. “There is strong evidence that such an event occurred during the Eemian period.”

Prof Hansen pointed to a range of evidence consistent with an imminent rapid sea level rise, including a brief time of rapid coral reef ‘backstepping’, and the vulnerability of the West Antarctic and later the East Antarctic ice sheets. “The eventual sea level rise for global temperatures expected by the middle of this century is at least 10 to 15 meters,” he concludes.

Major cities at risk of being submerged in this way include New York City, Mumbai, Lagos, Shanghai, Miami, Dhaka and Tokyo. 

“The fact is that ice sheet disintegration is an exponential process with a characteristic time-scale (doubling or e-folding time that characterises exponential growth) of 10 to 20 years at maximum,” says Prof Hansen’s memo. “That statement is proven by the fact that sea level rise of several meters per century has occurred many times in Earth’s history.”

The UN IPCC has under-estimated this danger due to simplistic ice sheet models that “are unable to reproduce rapid changes of sea level that occur repeatedly in the paleoclimate record,” Hansen states.

‘Business as usual’ growth of greenhouse gases, he further argues, “likely will cause shut-down of the overturning North Atlantic and Southern Ocean overturning circulations by the middle of this century”.

Both circulation systems play a critical role in regulating the stability of the Earth’s climate system. Recent models show that their shut-down could bring extreme cold to Europe and parts of North America, raise sea levels along the US East Coast, disrupt seasonal monsoons that provide water to much of the world, and further endanger the Amazon rainforest and Antarctic ice sheets. 

According to Prof Hansen, the most important effect may be reducing heat transfer from the southern to northern hemispheres, which would increase warming of the Southern Ocean at depth, accelerating Antarctic ice melt and driving sea level rise.

“Continued growth of present Antarctic ice melt with the characteristic doubling time implied by paleoclimate data yields sea level rise of several meters near the end of the present century,” he writes.


Is it Really Too Late?

According to Prof Hansen’s successor at the NASA Goddard Institute for Space Studies – climatologist Dr Gavin Schmidt – while it is “possible” that the Earth breaches 1.5°C this decade, it will “certainly” happen in the 2030s.

“I share his pessimism on the 1.5°C level, but I’m less confident of claims that we will inevitably breach 2°C”, Dr Schmidt told Byline Times. “It’s very hard to put a probability level on society’s likelihood of enacting policies.”

There is also good reason to believe, contrary to Prof Hansen’s pessimism about renewables, that we will be able to transform the global energy system far more rapidly than conventionally believed possible. 

One of the latest studies on this by Oxford University’s Institute for New Economic Thinking has found that solar, wind and batteries will be able to completely replace fossil fuels as early as 2040, saving $26 trillion in energy costs. 

Ultimately, the clean energy transformation is inevitable, because it is being driven by fundamental economic factors that will make solar, wind and batteries vastly cheaper and more competitive than oil, gas, coal, nuclear and hydropower. Those industries will be disrupted and replaced over the next two decades or so, but we will be able to extend their life a bit longer with regressive policies. If we delay too long by futilely trying to maintain business as usual, Prof Hansen is right – we would still enter a 2°C world by mid-century.

A spokesperson for the Cabinet Office told Byline Times that “COP26 was a historic success with almost 200 countries coming together in the UK to commit to take action on climate change and forge the Glasgow Climate Pact. This outcome means we can keep the goal of limiting global temperatures from rising more than 1.5 degrees alive.”

“The UK now holds the Presidency until COP27 in Egypt later this year,” the spokesperson added: “We will spend the coming months working with governments, businesses and civil society to make sure they deliver on the Glasgow Climate Pact, turning momentum into action.”

While it now looks virtually inevitable that we will hit the climate danger zone, we can still avoid some of the more catastrophic outcomes described by Prof Hansen – and act rapidly to get out of the danger zone as quickly as possible. 

As Byline Times has previously reported, research by technology forecasting think tank RethinkX suggests that we can reach 100% clean energy by the early 2030s, with the right societal choices. Most crucially, this system would produce three to four times the energy of the current fossil fuel system at zero marginal costs at most times of year – making carbon withdrawal technologies which are exorbitantly expensive today truly affordable for the first time. This would allow us to reduce new emissions to zero and then start getting existing emissions out of the atmosphere. 

Prof Hansen’s shocking analysis hits home the extent to which we are walking an extremely thin line. All the tools of transformation are not just within our reach, but already in our grasp – but only if we stop deluding ourselves with spectacles such as COP26 will we be able to use them.

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