Science has a stark message for us all. In this decade, we could lose the fight for the Paris Agreement climate goals, with profound consequences for life on Earth, now and in the future. On our current emissions trajectory—with global heat-trapping emissions continuing to rise except for a brief dip due to last year’s economic crisis—we’re at grave risk of doing so. Global average temperatures keep increasing too, with 2020 ending the hottest decade on record. It’s time we own the gravity of the science, recognize that this is a fight for our collective future, and make the only moral choice: break with the fossil-fueled past and go all-in for a clean energy future.

After promising to be guided by climate science and quickly rejoining the Paris Agreement, President Biden must now lead the United States to go big on climate action. He just announced a major domestic infrastructure plan, which includes significant clean energy and climate resilience investments. He will soon host an Earth Day Summit, where key world leaders will be pressed to make new, enhanced commitments—so-called nationally determined contributions (NDCs)—to reduce their global warming emissions. The U.S. NDC—slated to be announced by the summit—must be ambitious.

More than 1,500 scientists and experts have sent President Biden a letter, calling on him to commit to cutting U.S. heat-trapping emissions at least 50 percent below 2005 levels by 2030, as part of the nation’s contribution to meeting the Paris Agreement goals. It’s a feasible and necessary goal—and only the floor for U.S. ambition. The scientific evidence and global equity arguments for the United States to go further by making deeper, swifter cuts in emissions are clear and compelling. Securing an ambitious NDC this year and then pushing for more prior to 2030 will be important.

There’s much more to do, including putting the United States on a path to net-zero emissions before 2050, helping other nations transition to a low-carbon economy, and building resilience to the climate change we’ve already unleashed around the world. The urgency is fierce.

U.N. Secretary-General António Guterres recently referred to the yawning chasm between the current global emissions trajectory and where we need to be by 2030 as “a red alert for our planet.” By the time of the next U.N. climate talks (COP26) in Glasgow this November, world leaders must chart an aggressive path to closing this gap. As one of the world’s wealthiest countries and the largest cumulative emitter, the United States must commit to ambitious emission reductions by 2030. Moreover, high ambition from a group of major economies can help catalyze additional action from laggard nations.

This urgent, rational call for deep cuts will inevitably face opposition from powerful interests, like the fossil fuel industry, which has successfully stalled action for decades in pursuit of profits over our collective future. The continued onslaught of disinformation, greenwashing and attempts to stymie serious policies must be met with facts and roundly rejected.

The remaining global carbon “budget”—the carbon we can emit and keep global temperatures below critical thresholds—is quickly being exhausted. The climate crisis is also a global equity challenge: how to divide up this dwindling carbon budget fairly, factoring past emissions of richer nations and leaving room for the aspirations of millions living in poverty, as well as future generations. By any reasonable calculation, the United States and other wealthy nations have already blown through more than their share of the budget and should commit to cutting emissions as quickly as possible.

Cutting U.S. emissions in half by 2030 is technically and economically within reach, as a growing array of studies and experts affirm. It’ll take robust economywide policies and investments, including: a transition to a 100 percent carbon-free power sector by 2035; strong carbon pollution standards for cars, trucks and buses while also ensuring at least 50 percent of new passenger vehicle sales are electric by 2030; sharp limits on methane emissions; and incentives in sustainable farming systems that build soil health, sequester carbon and reduce emissions. Forty percent of the benefits of these investments should flow to historically disadvantaged communities, and there must also be fair transition packages for coal workers and coal-dependent communities. Done right, these policies can help reduce the enormous public health burden of fossil fuel pollution, address long-standing environmental injustices, create well-paying jobs and jump start our economic recovery.

Winning the climate fight will take multitrillion-dollar investments, while generating much more in benefits. Losing it will, as hundreds of economists recently affirmed, cost more than we can ever afford. With just over 1 degree Celsius of global average temperature increase, we’re already witnessing devastating impacts: deadly heat waves, rapidly intensifying and destructive storms, longer and more intense wildfire seasons, and increasing flooding and drought. A clear-eyed look at the science in 2021 shows that what some would call bold, is really about ensuring basic survival.

For both of us, this is also personal. We have done years of research on climate impacts and solutions. We’ve advocated strenuously for bolder ambition. We’ve marched in the streets, together with our children. We’ve experienced hope—when Congress nearly passed a climate bill, when the Paris Agreement was reached, when it seemed the devastation of hurricanes and wildfires in our nation would force a much-needed reckoning.

And each time we’ve felt the heartbreak of a return to business as usual. Enough. Business as usual is broken. It’s killing people, species and ecosystems, and jeopardizing the future. It’s wreaking disproportionate harm on communities of color and low-income communities, reinforcing structural racism and socioeconomic inequities.

This time, policy makers—starting with President Biden—have to break with the past. They must commit to making deep cuts in heat-trapping emissions, investing in a thriving clean-energy economy and building a more resilient, just and equitable nation. Anything less would be immoral.