Thirty years ago, a NASA scientist, James Hansen, told lawmakers at a Senate hearing that “global warming is now large enough that we can ascribe with a high degree of confidence a cause-and-effect relationship with the greenhouse effect.” He added that there “is only 1 percent chance of accidental warming of this magnitude.”

By that, he meant that humans were responsible.

His testimony made headlines around the United States and the world. But in the time since, greenhouse gas emissions, the global temperature average and cost of climate-related heat, wildfires, droughts, flooding and hurricanes have continued to rise.

This fall, the United Nations Intergovernmental Panel on Climate Change released an alarming report warning that if emissions continue to rise at their present rate, the atmosphere will warm up by as much as 2.7 degrees Fahrenheit (1.5 degrees Celsius) above preindustrial levels by 2040, resulting in the flooding of coastlines, the killing of coral reefs worldwide, and more catastrophic droughts and wildfires .

To avoid this, greenhouse gas emissions would need to fall by nearly half from 2010 levels in the next 12 years and reach a net of zero by 2050. But in the United States, the world’s second-largest emitter of greenhouse gases, President Trump continues to question the science of climate change, and his administration is rolling back emissions limits on power plants and fuel economy standards on cars and light trucks, while pushing to accelerate the use of fossil fuels. Other major nations around the world aren’t cutting emissions quickly enough, either.