Changing climates

Changing climates

James Hansen arrives – at his first ever COP

David Holmes

There is excitement for many at the Paris summit at the arrival of someone Naomi Klein called this week the grandfather of climate science.

James Hansen, who is credited with sounding the first alarm on climate change in the 1980s, is a radical climate systems analyst whose understanding of global warming is informed by his expertise in the climate of another planet – Venus – which underwent a runaway greenhouse effect.

It is difficult to overstate the impact of Hansen’s work on the exponential growth in climate research and public awareness around the world since the 1980s. And here is how the fable goes.

On a scorchingly hot Washington day, June 23, 1988, Hansen, a senior NASA climate scientist, testified before the Energy and Natural Resources Committee of the US Senate that, globally, 1988 was:

… warmer that at any time in the history of instrumental measurements.

Hansen proclaimed that something known as an enhanced “greenhouse effect” had become strong enough to trigger severe weather events, and that there was only a 1% chance that this effect was not caused by human activity.

The next day, the New York Times ran a headline, echoed by mass media around the world, that:

Global warming has begun.

Hansen’s testimony became a “story” that inaugurated a media current which changed environmentalism forever. Here was an agenda-setting threat that could be tied to tangible catastrophes – not only for other living beings on the planet, but for human beings themselves.

However, unlike your typical media current – which lasts for a few days, completely and utterly grips us until it becomes old news, sublimated and forgotten – the current of the climate crisis simply won’t go away.

As director of the Goddard Institute for Space Studies from 1981 to 2013, Hansen oversaw some extraordinary research.

With so much funding and resources available – such as an impressive array of satellites that could measure ice sheet melt, surface and upper troposphere temperature patterns – Hansen was able to come up with studies that would integrate the various areas of climate forcings, climate model development, earth observations, atmospheric radiation, atmospheric chemistry, climate impacts, planetary atmospheres, paleoclimate, and other disciplines.

Hansen would regularly co-publish with scientists from a range of areas.

Whereas most contemporary climate science is characterised by a very strong division of labour that is found in IPCC source articles, Hansen was always able to bring together these areas with his institute and without the bureaucratic inertia that the IPCC is famous for.

Hansen has long criticised the IPCC for being too conservative. In his sobering 2009 book Storms of My Grandchildren: The Truth about the Coming Climate Catastrophe and Our Last Chance to Save Humanity, he is sceptical about the gradualism of IPCC reports. For Hansen:

…climate change is non-linear and capable of strong changes over a period of a few decades.

For example, Hansen has challenged IPCC 2007 projections of sea level rise as potential underestimates that will “encourage a predictable public response that projected sea level change is moderate” and warns of the “danger in excessive caution” in the forecasts of climate change science.

Hansen differs from IPCC estimations of dangerous thresholds, and considers that CO₂ needs to be brought back to 350 parts per million. Although he prefers to use atmospheric composition of carbon as the targets we should be aiming for, I asked him on Wednesday whether, given that the conference’s terms of reference is temperature, where he would draw the line from a scientific standpoint as to what constitutes dangerous climate change, and whether 2℃ being put up as a guardrail is already dangerous in his view.

Hansen replied:

Yes absolutely. 2℃ would make it warmer than the Eemian interglacial period in which sea level was 6-8 metres higher than now.

Hansen said we are on the edge of handing our children a climate system that will be out of their control. “Disintegration of ice sheets and sea-level rise of many metres which would mean we would lose all coastal cities, and more than half of the largest cities in the world are on coastlines,” he said.

Given the interdependence of global cities, this would produce chaos for global society.

Hansen’s view is that a COP target of 2℃ is simply out of touch with what the science tells us. This is because little attention is being paid to climate inertia or “committed warming”. Oceans would rise due to the combined effects of thermal expansion and fresh water ice sheet melt whereby the visible melting of ice sheets and shelves, in Greenland and Antarctica, is both cause and effect of a higher global ocean temperature.

I also asked Hansen whether the science that is represented in the IPCC’s most recent Assessment Report is adequate to base this conference on.

No, I don’t think it is. My principal concern is that they do not include in their theoretical modelling fresh water from melting ice sheets … even with the current rates it is beginning to have an effect – it is cooling the southern ocean around Antarctica and I argue that the ice sheet mass loss is a non-linear process, which is better characterised as a doubling time than as a linear process. And in that case, we could, if we stay on business as usual, get sea level rise of several metres this century.

Given the credit given to Hansen in raising the alarm on climate it is a curious anomaly that he hasn’t ever attended UNFCCC conferences. On Thursday, at another event, Hansen declared:

The reason I came to this conference is that I could smell the same trick that they played at Kyoto, that they are going to pretend that they have done something important. That if they don’t agree on a carbon fee (a reference to his fee and dividend idea) then they are going to be kicking the problem down the road and we will have to deal with it there and we will still have to come back to this at the next COP. If fossil fuels are allowed to continue to be the cheapest fuel in the view of the public then we are going to keep burning them. We have got to come to grips with the fundamental problem which is pricing in the external costs.

By this, Hansen means pricing in health and the cost of adaptation to a very different world. If you price in these, everything is cheaper than fossil fuels.

Since retiring in 2013 Hansen has become more active in communicating the science we should be taking note of and his idea of a fee and dividend approach to carbon pricing, which The Conversation’s Michael Hopkin explored in an interview with Hansen this week.

At the Thursday event Hansen also came out in support of nuclear, with three other climate scientists – Tom Wigley, Ken Caldeira and Kerry Emanuel – in an event billed as:

… a stark challenge to world leaders and environmental campaigners attending the COP21 climate summit at a scheduled press conference in Paris on December 3.

They argued that nuclear has to be brought back into the toolkit alongside renewables given how much committed warming is in the pipeline. Renewables cannot do it alone, they argued. And as much as nuclear is demonised – with one scientist explaining how he had been arrested at an anti-nuclear power rally in his youth – it is the price humanity has to pay for failing at the last 24 years of COPs.

Nuclear power is back on the table at Paris as a major climate mitigation option. It features in the Intended Nationally Determined Contributions (INDCs) of big-league emitters like China, the US and India. They argued that we should put the stigma around nuclear reactors behind us, as improved light-water reactors, and fourth-generation reactors that produce virtually no waste, come online.

But the thorny issue of timescale was not really addressed by these scientists. Even if nuclear can be made safe, the reactors take 15-20 years to commission. And as Hansen himself argues elsewhere, we need solutions faster than that.

Nevertheless, the four scientists argued that the anti-nuclear position of some governments and NGOs is in fact causing unnecessary and severe harm to the environment and future generations.

This post was amended on December 4, 2015, to clarify Hansen’s quote about coastal cities and sea-level rise.

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