By Rebecca Hersher, Lauren Sommer
Excerpt:
World leaders are heading into the final days of COP30, the United Nations climate meeting in Brazil. They are trying to agree on how to curb global warming and pay for the costs of an increasingly hotter planet.
For the past eight years, one of the primary objectives of the annual negotiations has been to limit global warming to 1.5 degrees Celsius, compared to the temperatures in the late 1800s. That temperature goal was established after a landmark international scientific report laid out the catastrophic effects of exceeding that amount of warming.
But that goal is no longer plausible, scientists say. Humanity has not cut planet-warming pollution quickly enough, and the planet will exceed 1.5 degrees Celsius of warming, likely in the next decade, according to a recent United Nations report.
However, all is not lost. If countries can cut overall greenhouse gas emissions in half by 2035, scientists say the planet would quickly return to lower levels of warming.
“We must move much, much faster on both reductions of emissions and strengthening resilience,” U.N. climate chief Simon Stiell told world leaders at COP30. Right now, countries are pursuing policies that would cut emissions by just 12% by 2035.
“The science is clear: We can and must bring temperatures back down to 1.5 [degrees Celsius] after any temporary overshoot,” Stiell said.
If countries follow through on current promises to reduce greenhouse gas emissions, the latest estimates suggest that Earth’s temperature will top out around 2.5 degrees Celsius of warming this century.
The latest science also makes clear the profound human costs of exceeding 1.5 degrees Celsius of warming, even temporarily. The planet has warmed about 1.3 degrees Celsius, according to the World Meteorological Organization. And communities are already experiencing more dangerous storms, flooding and heat waves.
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Change No. 1: Coral reefs could be gone forever
For coral reefs, the tipping point may have already begun. Widespread coral die-offs have been seen around the globe as ocean temperatures heat up, making it the first domino to fall, according to a new report.
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Change No. 2: Ice sheets in Greenland and West Antarctica could collapse
Ice sheets are the massive frozen expanses that cover Greenland and Antarctica and contain about two-thirds of the freshwater on Earth. Climate change is already causing them to melt and raising sea levels around the world.
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Change No. 3: Permanently frozen ground is thawing
Climate change is causing permafrost — the permanently frozen ground in the Arctic — to thaw. And as the Earth approaches 2 degrees Celsius of warming, that thawing ground will cause both local and global problems.
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