It’s rare for scientists to call something a clear and unequivocal fact. But that’s exactly what a group of 11,258 scientists from around the globe are saying in a new paper.

“Earth is facing a climate emergency,” they wrote, “and scientists have a moral obligation to clearly warn humanity of any catastrophic threat.”

It’s apparently the first time such a large group of scientists has made such stark warnings.

The statement, spearheaded by Oregon State University scientists William Ripple and Christopher Wolf, was published Tuesday in the journal BioScience, 40 years to the day after the first World Climate Conference in Geneva in 1979. They argue that scientists have been warning about climate change ever since, but greenhouse gas emissions are still rising.

“Climate change has arrived and is accelerating faster than many scientists expected,” Ripple said in a press release.

To make the threat of climate change clear, Ripple and Wolf looked at more than just global surface temperature. They mapped tree loss over the globe and in the Amazon. They looked at population growth, fertility rates and an increase in greenhouse gas-producing agriculture.

Climate change, the authors say in the paper, is “more severe than anticipated, threatening natural ecosystems and the fate of humanity.” But there are steps we can take to mitigate it.

The paper outlines a series of policy moves that the people of the world will need to mitigate the worst impacts of climate change, among them:

• Eliminating fossil fuel subsidies and making a transition from fossil fuels to low-carbon renewable energy.

• Reducing the use of short-term pollutants like methane immediately.

• Switching to a more plant-based diet.

• Curbing population growth by making family planning readily available.