CNN  — 

Beto O’Rourke on Monday released his plan to tackle climate change in his first major policy proposal as a 2020 candidate.

O’Rourke plans to invest $5 trillion over 10 years in infrastructure and innovation and also sets a goal to achieve net-zero emissions by 2050, according to an outline of O’Rourke’s proposal which his campaign put out ahead of a tour of Yosemite National Park on Monday.

The former Texas Democratic congressman’s plan called climate change “the greatest threat we face” and outlined a four-part framework to address this “existential threat” and “growing emergency.”

If elected president in 2020, O’Rourke’s “very first bill he sends to Congress … will mobilize $5 trillion over 10 years — spurred by the single largest investment to fight climate change in history — to transform our aging infrastructure, accelerate innovation, and empower our people and communities to lead the climate fight,” according to his plan.

O’Rourke’s ambitious, first major policy rollout comes amid questions from voters and critics about how he would take on key issues should he be elected president.

Climate change has become a major issue for 2020 Democrats in the wake of a stark 2018 report from the global scientific authority that says governments around the world must take “rapid, far-reaching and unprecedented changes in all aspects of society” to avoid disastrous levels of global warming. The planet has only until 2030 to stem catastrophic climate change, the report, issued by the UN Intergovernmental Panel on Climate Change, warns.

According to his proposal, O’Rourke’s $5 trillion mobilization would be “directly leveraged by a fully paid-for $1.5 trillion investment,” and the bill he would introduce to Congress would be funded by “changes to the tax code to ensure corporations and the wealthiest among us pay their fair share and that we finally end the tens of billions of dollars of tax breaks currently given to fossil fuel companies.”

O’Rourke plans to take “a series of forceful executive actions to start cutting pollution across all sectors of the economy” on his first day in office, and re-enter the Paris agreement, a global accord on reducing harmful emissions that President Donald Trump withdrew the US from in 2017.

The plan says O’Rourke would “lead the negotiations for an even more ambitious global plan for 2030 and beyond.”

Earlier this month, when asked by CNN if re-entering the Paris climate agreement would be the first thing that would get his signature if he becomes president, O’Rourke said, “It is among a number of things that I want to do,” also listing protecting Dreamers and people protected by the Deferred Action for Childhood Arrivals program as well as reversing “the effort to ban Muslim travel,” as his day one priorities.

O’Rourke’s climate change plan would “set a first-ever, net-zero emissions by 2030 carbon budget for federal lands, stopping new fossil fuel leases, changing royalties to reflect climate costs, and accelerating renewables development and forestation.”

“We need a guarantee that we will, in fact, achieve net-zero emissions by 2050 and get halfway there by 2030,” according to the plan. “For this reason, Beto will work with Congress to enact a legally enforceable standard — within his first 100 days.”

The emission reduction goal is in line with the Green New Deal, a broad policy proposal from progressive Democrats to battle climate change among other issues, which is backed by several 2020 Democrats, including O’Rourke.

“By investing in infrastructure, innovation, and in our people and communities, we can achieve this ambition, which is in line with the 2050 emissions goal of the Green New Deal, in a way that grows our economy and shrinks our inequality.”

He will focus on “defending our communities … that are preparing for and fighting against fires, floods, droughts, and hurricanes.”

When asked who is advising O’Rourke on energy, a campaign spokesperson told CNN, “Beto consulted with impacted individuals and communities, academics, scientists, entrepreneurs, advocates and activists, and local, state, tribal, and federal government leaders.”

“Throughout this campaign, he has listened to Americans all across the country and made their ideas and concerns part of his platform as he he’s held 113 town halls in 88 cities and answered 625 questions,” the spokesperson said. “That’s how he learned more about record f(l)ooding in Iowa, drought in Nevada, a fight over offshore drilling in South Carolina, historic conservation efforts in New Hampshire, plans to protect the water and forests of Virginia, and wind and solar job growth throughout Texas.”

CNN’s John Sutter contributed to this report.