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When Donald Trump pulled out of the Paris Agreement on Climate Change earlier this year, Stephen Hawking did not hesitate to publicise his horror.
“Trump's action could push the Earth over the brink, to become like Venus, with a temperature of two hundred and fifty degrees, and raining sulphuric acid," he told the BBC. The decision of one man, damaging decades of increasing global political awareness of the urgent nature of climate change, would cause “avoidable environmental damage to our beautiful planet" he added.
Read more: The 10 facts that prove we're in a climate emergency
Today, three papers have been published in Nature Climate Change that effectively cement Hawking’s dire predictions for our collective future, and suggest the Paris Agreement, which aims to keep the increase in global average temperature below 1.5C, will not be enough. Especially in light of US policy decisions.
One paper uses statistical models based on five decades of historical data to predict a 90 per cent chance of warming falling between 2C and 4.9 C this century; a second suggests if we continue to emit current emissions at their current rate, it will take just 15 years to see a 1.5C rate of warming. Even a rise of 1.5C will prove hugely damaging to global food production and clean water sources. Rates of 2C are considered to be catastrophic and likely to lead to increasingly extreme climate events.
A third study looks at the deadly consequences of inaction: using existing models, a University of North Carolina at Chapel Hill team estimates that premature deaths resulting from the ozone and particulate matter will reach 60,000 by 2030 and 260,000 by 2100.
In “Less than 2C warming by 2100 unlikely”, a University of Washington team looked at the impact of global population, GDP and carbon intensity (the amount of carbon emitted for every dollar of economic activity) on future carbon emissions, looking at trends from the past 50 years. Its models found there is a 1 per cent chance of warming remaining below the 1.5C Paris Accord aim. The answer? Policy makers need to address the question of carbon intensity, say the team.
“It is the only [factor] under policy control to some extent in the medium term,” lead author, and professor of statistics and sociology, Adrian Raftery, told WIRED. “Reducing GDP would be another way to reduce carbon emissions, but policies to do this are of course unlikely.”
Coauthor Dargan Frierson, associate professor of atmospheric sciences, said: "Our results show that an abrupt change of course is needed to achieve these goals."
Policy changes should focus on reducing carbon fuel use, they argue, suggesting a carbon tax, cap or trade system. It’s of note that president Trump has appointed an astonishing 16 people to government positions, including in the Environmental Protection Agency and the Department of Energy, that have ties to the fossil fuel industry, according to this Vox post keeping tabs.
Raftery also suggests an increased research focus on technologies that could improve carbon efficiencies, as LED lighting did, and learning from the countries making the best progress.
France, for instance, has “a major and efficient public transportation network, with carbon-efficient high-speed trains crisscrossing the country, a high gas tax, and most of their electricity is produced by nuclear power, which produces almost zero carbon emissions”.
In contrast, he said, the long term impact of the US pulling out of the Paris Accords will “certainly be a negative one”, though the team has not done calculations based on the latest policy changes. Although carbon intensity has been steadily decreasing in recent years, the US policy change could change this as well, Raftery points out.
Speaking to WIRED, coauthor Dick Startz, an economist added: “I would remind the Trump administration something about real estate… It’s really hard to make money on real estate that’s under the ocean. That’s where a lot of American real estate is going to be (notably in Florida) if we don’t change course.” It’s a stark image that might sit with the Trump Towers owner longer than climate change stats.
Barring any “breakthrough technology”, our best bet will be to focus on carbon intensity, and therefore a concerted commitment from policymakers. Raftery points out that although we have seen “dramatic technical advances in the last 50 years”, history has taught us that their impact on carbon efficiency has been incremental. The data his model is based on covers 1960-2010, when advances including LED lighting, computing, fracking, the internet, robotics and much more, took place. Even so, these have led to steady improvements in carbon efficiency of 2 per cent each year “and not by sudden jumps”.
The second Nature Climate Change paper, “Committed warming inferred from observations”, echoes this sentiment, that a dramatic shift is not possible. It also looks to the past, drawing on observations of historical warming and how much heat is taken by the oceans, to prove that we are still playing catchup with climate change. According to the study, if we could turn off all our emissions of greenhouses – a complete impossibility – temperatures would still rise by 1.3C. “We’ve reached similar conclusions, but for different reasons,” coauthor Robert Pincus of the University of Colorado Boulder tells WIRED, referring to the UW paper. “Theirs looks at social realities, ours looks at committed warming by physical realities.”
He still maintains the predictions are not a foregone conclusion. Pincus points out that his coauthor, Thorsten Mauritsen from the Max Planck Institute for Meteorology, wanted to do the study because he did not believe the Paris Accord’s 1.5C target was even possible. “It is plausible,” says Pincus. “2C remains even more plausible.”
Their approach, he says, provides a simplified scenario that allows us to see “how much responsibility the past owes to the future”.
“If we do not make strong efforts to reduce our emissions then the likelihood the planet will warm to temperatures that other people have considered not sustainable, that likelihood continues.”
“What we’ve provided here maybe speaks to those that don’t put faith in climate models – ours is not a [traditional climate change model but] found exactly the same results.”
This article was originally published by WIRED UK
