Posted on 7 September 2015 by dana1981

Actress and Greenpeace activist Emma Thompson was interviewed on BBC Newsnight about Shell’s drilling in the Arctic and associated climate change threats. In the interview, Thompson made some inaccurate statements about the timescales associated with those climate threats. However, her concerns are generally justified.

 Emma Thompson on BBC Newsnight.

Many critics have latched onto the following inaccurate statement,

if they take out of the earth all the oil they want to take out, you look at the science – our temperature will rise 4 degrees Celsius by 2030, and that’s not sustainable.

This is incorrect. According to the latest IPCC report, by 2030, global surface temperatures probably won’t be more than 2°C hotter than pre-industrial levels. A 2010 study led by Met Office climate scientist Richard Betts called “When could global warming reach 4°C?” answered the titular question as follows,

…our best estimate is that the [fossil fuel intensive] emissions scenario would lead to a warming of 4°C relative to pre-industrial during the 2070s. If carbon-cycle feedbacks are stronger, which appears less likely but still credible, then 4°C warming could be reached by the early 2060s

So, Thompson was off by three to four decades. However, because of the lag between the time when we emit greenhouse gases and when their full warming influence in realized, the highest emissions scenario considered in the latest IPCC report suggests we would commit ourselves to 4°C warming by 2050. 

That day could arrive even earlier because as the Betts study noted, carbon-cycle feedbacks may be stronger than currently simulated in climate models. Moreover, it takes time to transition our infrastructure away from fossil fuels. If we haven’t taken major steps in that direction in the coming years, we’ll commit ourselves to a very hot planet.

Additionally, 4°C represents a potentially catastrophic scenario. At 3–4°C warming, 40–70% of global species would be at risk as we continue on the path toward the Earth’s sixth mass extinction. Glacier retreats would threaten water supplies in Central Asia and South America. The possibility of significant releases of carbon dioxide and methane from ocean hydrates and permafrost could amplify global warming even further beyond our control.

Even 2°C is considered a point beyond which international negotiators have agreed we should not pass because of the potentially dangerous consequences. At 2°C warming, coastal flooding will impact millions of people, coral bleaching will be widespread (exacerbated by ocean acidification), global food crop production will decline, and up to 30% of global species will be at increasing risk for extinction.

 Denial101x climate impacts lecture by Dana Nuccitelli.

If we continue on the fossil fuel intensive pathway that Emma Thompson was talking about, we would commit the planet to 2°C warming by 2020–2030, and 3°C by 2030–2040. Hence while her numbers were wrong, the case she was making for the urgency of action is generally both correct and important.

Thompson also expressed concern about the potential of increased migration due to climate change making some areas uninhabitable for humans.

Our refugee crisis – which, let me tell you, if we allow climate change to go on as it’s going, the refugee crisis we have at the moment will look like a tea party, compared to what’s going to happen in a few years’ time. Because if we allow climate change to continue, there are going to be entire swathes of the Earth that will become uninhabitable, and where are those people going to go? Where do we think they’re going to go? We’re looking at a humanitarian disaster of proportions we simply can’t imagine.

Thompson again exaggerated the timescales by saying “in a few years’ time.” However, the concern she expresses is a valid one. Unchecked sea level rise would eventually make many low-lying island nations and coastal cities uninhabitable, for example. Intensified extreme weather events such as droughts could significantly reduce agricultural productivity in other areas, as some research has suggested happened in Syria. Too much warming could even make some regions unbearably hot, although likely not until next century.

Timing wrong, but concerns valid

Ultimately, as Richard Betts noted,

while Ms Thompson’s concerns are valid in the longer term, her timing isn’t supported by the science.

While catastrophe isn’t imminent by 2030, the coming decade will be critical in transitioning away from our current high fossil fuel, high risk scenario. It’s also worthwhile to note, as one blogger pointed out,

When someone like Emma Thompson gets something wrong, you won’t easily find people promoting it. Typically – as has happened here – people point out the errors and accept that those who speak publicly about this should make sure that they’re sufficiently informed. When someone like Booker, or Ridley, gets something wrong, it gets promoted on various denialist blogs as highlighting problems with climate science.

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