WASHINGTON — Now that President Donald Trump withdrew the U.S. from the Paris Agreement on climate change on Thursday, here’s what you need to know about the international effort and how the decision could impact the environment.

What is the Paris Agreement?

The Paris Agreement is a deal reached between 195 countries to gradually reduce emissions that cause climate change in order to prevent a major increase in the global temperatures that could raise sea levels, spark major droughts, and lead to more dangerous storms.

The agreement, which was negotiated in 2015 and took effect in November 2016, was spurred by the overwhelming global scientific consensus that rising global temperatures over the last several decades are caused by man-made activity. The United Nations Intergovernmental Panel on Climate Change, which pools scientific research from around the world, concluded that greenhouse gas emissions were “extremely likely to have been the dominant cause of the observed warming since the mid-20th century” with more than 95 percent confidence.

Climate change is already impacting the planet, but the specific goal of the Paris Agreement is to prevent the world from warming by more than 2 degrees Celsius (3.6 degrees Fahrenheit), which scientists warn could have especially damaging consequences.

What does the U.S. have to do?

The agreement, which is not a binding treaty, calls on countries to make voluntary national pledges to reduce emissions and provide periodic updates on their progress.

President Barack Obama committed America to a goal of lowering emissions by 26 percent to 28 percent below 2005 levels by 2025. These targets aren’t fixed forever, though, and the broad aim is to increase them over time.

The agreement also hinges on developed countries like the United States, whose economies have contributed more emissions historically, helping to finance developing countries’ transition to cleaner forms of energy. The plan is to raise $100 billion a year through a mix of public and private sources.

On the U.S. side, Obama transferred $1 billion out of an initial $3 billion commitment to the United Nations Green Climate Fund before leaving office. But the recent spending deal in Congress, which funds the government through September, left out any contributions to the fund.

Why is Trump withdrawing?

There are a number of aspects of the climate deal that run counter to the president’s worldview.

One, Trump does not accept the dominant scientific consensus on climate change and has a penchant for conspiracy theories that cast experts like researchers, doctors, or government agencies in the role of villain. He has repeatedly tweeted and said in campaign speeches that climate change is a “hoax” and even suggested that China — another frequent Trump target — was behind the plot. Trump later said the accusation was a joke, but he has said he doesn’t believe China will follow through on its promises to reduce their use of fossil fuels.

Two, Trump is a skeptic of international agreements and institutions in general, which he often complains tie America down with obligations that don’t provide enough concrete benefits in return. In addition to the Paris Agreement, Trump has rattled allies by criticizing trade agreements and military alliances.

Environmental Protection Agency Administrator-designate, Oklahoma Attorney General Scott Pruitt testifies on Capitol Hill in Washington, on Jan. 18, 2017, at his confirmation hearing before the Senate Environment and Public Works Committee. J. Scott Applewhite / AP

Three, Trump is not a fan of the regulations and spending that the previous administration proposed to meet its goals, which he warns will reduce economic growth. He appointed a prominent climate skeptic to run the Environmental Protection Agency, Scott Pruitt, and is rolling back the Obama administration’s Clean Power Plan, which was set to reduce power usage by coal plants in favor of cleaner forms of energy. Trump campaigned on reviving the coal industry and has expressed displeasure with some forms of renewable energy, especially wind.

These objections aren’t unique to Trump. Many conservatives opposed the Paris Agreement on similar grounds and have pushed him to withdraw. Trump said Thursday that he remains open to renegotiating a better deal for the U.S. to return to the Paris agreement.

What happens now?

The agreement won’t fall apart overnight. Already, reports suggest China and the European Union are prepared to publicly recommit to the agreement. Some experts say China appears to be reducing emissions ahead of schedule, in part because the country is phasing out coal quicker to reduce choking smog in its major cities.

Trump also can't technically can't begin to withdraw from the agreement until November 2019 at the earliest.

It’s an open question whether the United States will hit its Paris emissions target with or without the agreement. The economy is already moving away from carbon-heavy energy sources like coal in favor of cleaner natural gas and increasingly affordable renewable energy. Trump’s actions may not be enough to alter that trend. In addition, states like California have pledged to pick up the slack if Trump withdraws by instituting their own environmental restrictions.

RELATED: Big business urges Trump to stick with Paris agreement

It’s also notable that some of the largest companies in industries that would be impacted most by climate regulation are supporting the Paris Agreement. For example, ExxonMobil, the oil giant whose former CEO Rex Tillerson is now Secretary of State, has publicly lobbied the White House not to withdraw.

“I actually think we might meet our target,” J. Timmons Roberts, an environmental studies professor at Brown University, told NBC News. “The technology is making the choices easier for people more quickly than expected.”

But supporters of the agreement warn the United States would, at a minimum, damage its relationship with close allies by bolting and cede more global influence to rivals like China. In a worst-case scenario, the move would discourage developing nations from taking further steps to limit emissions, potentially hampering efforts to reduce emissions before dangerous temperature increases are locked in.

A lot of this depends on expectations. If participating nations and industry leaders assume the United States exit is only a temporary bump and that future presidents will return to the table and pursue similar policies as Obama, that could also make them reluctant to take actions based on Trump’s decision alone.