The Earth has already warmed 1 degree Celsius (1.8 degrees Fahrenheit) since the 19th century. Now, a major new United Nations report has looked at the consequences of jumping to 1.5 or 2 degrees Celsius. Half a degree may not sound like much. But as the report details, even that much warming could expose tens of millions more people worldwide to life-threatening heat waves, water shortages and coastal flooding. Half a degree may mean the difference between a world with coral reefs and Arctic summer sea ice and a world without them. Arctic 1.5°C Sea ice will remain during most summers. 2°C Ice-free summers are 10 times more likely. An additional half-degree of warming could mean greater habitat losses for polar bears, whales, seals and sea birds. But warming temperatures could benefit Arctic fisheries. Extreme heat World population exposed to severe heat waves (like one that blanketed southeastern Europe […]