Two decades. That's all the time world leaders have to reverse emissions of greenhouse gases to avoid inundating coastal cities, killing off coral reefs and their attendant marine wildlife, and potential food shortages, according to a new UN report by the Intergovernmental Panel on Climate Change.
The report was the first commissioned by world leaders under the Paris Climate Accord from which President Trump is withdrawing the U.S. and was first covered by The New York Times.
Climate scientists have been studying the effect of a global temperature rise of 3.6 degrees Fahrenheit (2 degrees Celsius) over preindustrial levels and have determined that is the maximum possible warming before sea level rise, drought, and other climate-change effects become catastrophic.
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The new report sets those levels much lower and measures devastating climate change effects much sooner. It concludes that if greenhouse gas emissions continue at the current pace, coastal flooding could become intense and droughts severe by 2040. The report pegs those effects at temperatures 25 percent less than previous studies—2.7 degrees Fahrenheit (1.5 degrees Celsius.)
The authors of the IPCC report estimate economic damages from flooding, drought, and other effects by 2040 of $54 trillion.
It notes that to prevent that such damage would require a cessation of global-warming emissions in just a few years—and acknowledges the political unlikelihood of such a solution, especially in the United States.
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For example, a recent economic impact statement by the EPA and NTHSA regarding rolling back fuel economy increases noted the reality of mad-made global warming and concluded that it isn't economical to address.
To provide sufficient incentive to reduce carbon emissions that quickly would require a carbon tax of $27,000, the report estimates—almost double the current price of emitting a ton of carbon under California's cap-and-trade program.
Although carbon emissions come from more than transportation, the transportation sector is far behind electricity production in making the switch to low-carbon energy sources. The International Energy Agency estimates that only 4 percent of transportation energy comes from renewable sources and anticipates that number will increase by only 1 percent by 2022.
The report landed on the same day that the Nobel Committee awarded the Nobel Prize in Economics to two American scientists for their work highlighting the role of government policy in promoting sustainable economic growth.
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