The Intergovernmental Panel on Climate Change, which issued the report, said that global average temperatures are estimated to rise 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels sometime around “the first half of the 2030s.” Beyond that point, scientists say, the impacts of climate change — catastrophic heat waves, crop failures and species extinction — will become much harder for humanity to handle.
To shift course, the report said, countries need to cut greenhouse gases by half by 2030 and stop emitting carbon dioxide altogether by the early 2050s. If those two steps were to be taken, the world would have about a 50 percent chance of limiting warming to 1.5 degrees Celsius.
Practically, that means retiring fossil fuel infrastructure or canceling planned projects. It also means efforts like expanding wind and solar energies, making cities friendlier to pedestrians and cyclists and reducing food waste.
However, global fossil-fuel emissions set records last year, while China and the U.S. continue to approve new fossil fuel projects. Under the current policies, Earth’s temperature is estimated to heat up by 2.1 to 2.9 degrees Celsius this century.