Stephen Hawking warned that pulling out of the Paris Climate Accord will have catastrophic consequences for our planet. "Trump's action could push the Earth over the brink, to become like Venus, with a temperature of two hundred and fifty degrees, and raining sulphuric acid," Hawking told BBC. The Paris accord intends to cut global emissions and to prevent temperatures from rising. "We are close to the tipping point where global warming becomes irreversible."