What does that mean for us? Well, the climate experts warn, as the temperatures reach that crucial threshold, the planet is likely to experience extreme droughts, floods, wildfires, loss of coral reefs and food shortages.
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The new research is a direct result of the 2015 Paris Climate Agreement, or the Paris Accord, a pact sponsored by the United Nations to bring the world’s countries together in the fight against climate change. Ninety-one authors and review editors from 40 countries helped prepare the report.
Under the Paris accord, nations set a goal to limit warming to 2.7 degrees Fahrenheit. The U.N. asked the IPCC to find out what it would take to reach that goal. The United States was initially part of the accord along with 197 other nations, but President Donald Trump withdrew the U.S. from the agreement last year.
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“There is no documented historic precedent” for what’s to come, the IPCC wrote in its new 700-page report, which makes it clear that we are currently seeing the impact of climate change before our eyes through rising sea levels, high-temp heatwaves, extreme overall weather and melting Arctic sea ice.
"Every extra bit of warming matters, especially since warming of 1.5 degrees C or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems," IPCC Wokring Group II co-chair Hans-Otto Pörtner said in the report.
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While it's possible to limit global warming to that threshold of 2.7 degrees Fahrenheit, "doing so would require unprecedented changes," Jim Skea, co-chair of IPCC Working Group III, said in a statement.
"The difference between possibility and impossibility is political will," Chris Weber, lead climate change scientist at World Wildlife Fund, also told the Independent.
Staying at or below the threshold would require decreasing global greenhouse gas emissions 45 percent below 2010 levels by 2030, according to the report. That may mean heavy taxes or prices on carbon dioxide emissions, drastic changes to transportation, infrastructure and energy — and reducing our coal consumption by one-third. Research authors estimate that avoiding the anticipated damage would cost approximately $54 trillion.
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"This report gives policymakers and practitioners the information they need to make decisions that tackle climate change while considering local context and people's needs. The next few years are probably the most important in our history," Debra Roberts, co-chair of IPCC Working Group II, said in a statement.
Explore the full UN report at ipcc.ch.