After decades of work to reach a universal agreement on global warming and climate change, the Paris Agreement for the first time brings all nations into a common cause of ambitious efforts to combat climate change and adapt to its effects. On Oct. 5, the legal threshold for the Paris Agreement was achieved, and on Nov. 4, it entered into full effect.

Then on Nov. 8, Trump was elected president. Trump says global warming is a “hoax,” and he will withdraw the U.S. from the Paris Agreement, or just ignore it.

But the Paris Agreement is just the start of Trump’s destructive plans. He will rescind President Obama’s Climate Action Plan, which outlines a wide array of actions to reduce carbon pollution, increase energy efficiency, expand renewable and other low-carbon energy sources, and strengthen resilience to extreme weather and other climate impacts.

Trump wants to dismantle the Environmental Protection Agency (EPA), eliminate the EPA’s Clean Power Plan to reduce carbon emissions from existing power plants. He will eliminate all clean energy funding. He will end aid intended to help developing nations mitigate climate change impacts. He will approve the Keystone and Dakota Access pipelines, threatening our air, land, and water. He will “lift the Obama-Clinton roadblocks” to allow these dangerous infrastructure projects to be developed. He will repeal “draconian climate rules” intended to slow global warming. He will stop “the war on coal” and escalate production of coal, oil and natural gas, increasing atmospheric greenhouse gas concentrations.

He has appointed Myron Ebell, a leading global-warming denier at the conservative Competitive Enterprise Institute, who has said global warming is “nothing to worry about” and that the EPA’s Clean Power Plan is “illegal,” to oversee “transition plans” for the EPA.

Trump’s shortlists for key administration posts are alarming. Oil billionaire Harold Hamm is proposed for energy secretary, while Sarah Palin has been floated as a candidate for interior secretary. Palin is an enthusiastic proponent of oil and gas drilling, and has described fossil fuels as “things that God has dumped on this part of the Earth for mankind’s use.” Never mind the destructive consequences.

In other words, Trump plans to send the world into an irreversible climate-catastrophe. According to Lux Research, U.S. greenhouse gas emissions will see a resurgence just when U.S. emissions were starting to decline. A Nov. 11 Guardian article states “the planet will likely spiral into runaway climate change where tens of millions of people are displaced by rising seas, food insecurity and conflict, leading to an unprecedented international humanitarian disaster.” Major U.S. cities, including New York, Miami and Boston, would face inundation. And California, already experiencing its worst drought in 1,200 years, may experience “mega-droughts” that last decades.

The Pentagon has warned climate change poses a “threat multiplier” to U.S. national security as more “failed states” and resource conflicts spread around the globe.

Michael Mann, climatologist and geophysicist, and director of the Earth System Science Center at Pennsylvania State University, states “A Trump presidency might be game over for the climate. It might make it impossible to stabilize planetary warming below dangerous levels.” Kevin Trenberth, senior scientist at the U.S. National Center for Atmospheric Research says “This is an unmitigated disaster for the planet.”

Benjamin Schreiber, climate director at Friends of the Earth-U.S. says “Millions of Americans voted for a coal-loving climate denier willing to condemn people around the globe to poverty, famine and death from climate change. It seems undeniable that the United States will become a rogue state on climate change.”

Professor Tom Lyon of University of Michigan business school, says “As president, Donald Trump will pretend climate change does not exist. This is an increasingly untenable position … His energy policy will encourage investment in high-carbon energy sources that will look foolish in retrospect. And he will anger much of the rest of the world by reneging on policies designed to address global challenges.”

Michael Oppenheimer, Princeton University professor of geosciences and international affairs, states “If Trump steps back from (the Paris Agreement), it makes it much less likely that the world will ever meet that target (of keeping warming below 3.6 degrees Fahrenheit), and essentially ensures we will head into the danger zone.”

So how are we to respond to Trump’s ignorant madness? First, we can’t give in to pessimism. We must stay focused on the goal of a sustainable, carbon-free energy future, and fight Trump and Republican denialism at every opportunity. This is OUR earth they are determined to destroy!

Michael Brune, Sierra Club executive director, says “If he tries to go backwards on climate change, he’ll run headlong into an organized mass of people who will fight him in the courts, in Congress and on the streets.”

Alex Steffen, planetary futurist, writes “Maybe climate action in America didn’t just end. Maybe it’s only just beginning.”

William Gran, now retired, was an adjunct instructor at Greenfield Community College on global warming and climate change. He can be reached at whgran@gmail.com