2018/10/07: landmark report from the United Nations’ scientific panel on climate change paints a far more dire picture of the immediate consequences of climate change than previously thought and says that avoiding the damage requires transforming the world economy at a speed and scale that has “no documented historic precedent.”
if greenhouse gas emissions continue at the current rate, the atmosphere will warm up by as much as 2.7 degrees Fahrenheit (1.5 degrees Celsius) above preindustrial levels by 2040, inundating coastlines and intensifying droughts and poverty. Previous work had focused on estimating the damage if average temperatures were to rise by a larger number, 3.6 degrees Fahrenheit (2 degrees Celsius), because that was the threshold scientists previously considered for the most severe effects of climate change.
Avoiding the most serious damage requires transforming the world economy within just a few years, said the authors, who estimate that the damage would come at a cost of $54 trillion. But while they conclude that it is technically possible to achieve the rapid changes required to avoid 2.7 degrees of warming, they concede that it may be politically unlikely.
The report emphasizes the potential role of a tax on carbon dioxide emissions. “A price on carbon is central to prompt mitigation,” the report concludes. It estimates that to be effective, such a price would have to range from $135 to $5,500 per ton of carbon dioxide pollution in 2030, and from $690 to $27,000 per ton by 2100.
“Carbon taxes are political poison because they increase gas prices and electric rates,” said Myron Ebell, who heads the energy program at the Competitive Enterprise Institute, an industry-funded Washington research organization, and who led the Trump administration’s transition at the Environmental Protection Agency.
The report details the economic damage expected should governments fail to enact policies to reduce emissions. The United States, it said, could lose roughly 1.2 percent of gross domestic product for every 1.8 degrees of warming.
In addition, it said, the United States along with Bangladesh, China, Egypt, India, Indonesia, Japan, the Philippines and Vietnam are home to 50 million people who will be exposed to the effects of increased coastal flooding by 2040, if 2.7 degrees of warming occur.
At 3.6 degrees of warming, the report predicts a “disproportionately rapid evacuation” of people from the tropics. “In some parts of the world, national borders will become irrelevant,” said Aromar Revi, director of the Indian Institute for Human Settlements and an author of the report. “You can set up a wall to try to contain 10,000 and 20,000 and one million people, but not 10 million.”
The report also finds that, in the likelihood that governments fail to avert 2.7 degrees of warming, another scenario is possible: The world could overshoot that target, heat up by more than 3.6 degrees, and then through a combination of lowering emissions and deploying carbon capture technology, bring the temperature back down below the 2.7-degree threshold.