MELBOURNE – The catastrophic outcome of last November’s United States presidential election is now clear. President Donald Trump’s indifference to the risk of climate change, and the actions he is taking because of that indifference, are likely to have consequences that dwarf the significance of his executive order on immigration, his nomination of an archconservative to the Supreme Court, and, should he manage to achieve it, his repeal of the Affordable Care Act (“Obamacare”).
With the exception of launching a nuclear war, it is hard to think of anything a US president could do that is liable to harm more people than last month’s order canceling rules issued under former President Barack Obama to freeze the construction of new coal-fired power plants and shut down many old ones. Trump’s order followed his pledge to rescind stricter fuel-efficiency standards for cars and trucks, and his announcement that he wants to slash spending on climate science.
Although Trump did not announce the withdrawal of the US from the Paris climate agreement, his actions are likely to prove incompatible with the US government’s pledge to reduce greenhouse-gas emissions to 26% below 2005 levels by 2025. The Paris agreement, signed by 195 countries, is our last real chance of keeping global warming to less than 2ºC above pre-industrial levels. Even 2ºC is too much for the inhabitants of low-lying island states. Many of these states were pleading for a 1.5ºC limit – without which some will disappear beneath the ocean.
Any increase in global temperature greater than 2ºC, scientists agree, risks triggering feedback loops that cause much greater warming and could render large parts of the planet uninhabitable. For example, further warming would release large quantities of methane – a more potent greenhouse gas than carbon dioxide – from thawing Siberian permafrost, leading to more warming, more thawing, and more methane in the atmosphere. Similarly, warming causes the loss of arctic ice, which means that less of the sun’s heat is reflected back rather than being absorbed by the ocean.