In climate news, a new report warns that without immediate, large-scale action to limit global greenhouse gas emissions, as much as 30 percent of the Earth’s land could fall into a state of perpetual drought, threatening the food supplies of billions of people. The report in the journal Nature predicts the desertification would follow a global average temperature rise of 2 degrees Celsius—or about 3.6 degrees Fahrenheit—by 2050. That’s the upper limit set by the landmark 2015 Paris climate accord, which has been embraced by every nation on Earth except the United States, under President Trump.