Presidencies are often made or broken within the first two years, so how is the Trump legacy looking at the two-year mark?

He boasts he has accomplished more in two years than any other president, but the Trump juggernaut is grinding to a halt, and it’s not just the record-breaking government shutdown or the Russia investigation. A Democratic-controlled House will likely slam the brakes on his remaining legislative agenda, including completion of any border wall. In the foreign policy arena his shoot-from-the-lip diplomacy will likely yield chaos and uncertainty, as it has in Syria. Go-it-alone policies rarely produce lasting legacies.

So where’s the enduring legacy?

Tax cuts? Tax changes are not carved in stone. President George W. Bush succeeded in reducing the top marginal income tax rate to 35.0 percent, but the top rate reverted to 39.6 percent in 2013. Mounting concerns about deficits and tax equity could force a future Congress to rein in the Trump tax cuts.

Trade policy? President Trump has forced our trading partners back to the negotiating table, but the revised NAFTA agreement is not a radical overhaul, and the trade war with China could easily end in a draw, albeit with high short-term costs.

But there are two areas where the Trump administration will likely have a lasting impact. The first is reproductive rights. The appointments of Neil Gorsuch and Brett Kavanaugh to the U.S. Supreme Court alone could mark an historical turning point, but Trump has also secured confirmation of 30 new appellate judges. One in six federal circuit court judges are now Trump appointees.

A significant challenge to abortion rights could come before the Court as early as this year. And, if Trump is able to appoint yet another associate justice to the Supreme Court before he leaves office, the odds of Roe v. Wade being overturned could rise dramatically. If it happens, Trump’s enduring legacy will be a return to unsafe abortions and a resulting increase in maternal deaths.

Trump’s most indelible legacy, however, could be environmental degradation. If a Democrat wins the White House in 2020, Trump’s anti-climate policies, like his tax cuts, could be reversed, but the harm they have inflicted could prove irreversible.

Despite the action steps formally agreed to at the COP24 climate conference in Poland last month, the world appears less and less likely to do what is necessary to keep the rise in average global temperatures below 2°C, let alone below 1.5°C. Without strong U.S. leadership, avoiding catastrophic warming is in mortal danger of becoming a mission impossible. A prominent research firm estimates that carbon emissions by the U.S. (the world’s second largest carbon emitter,) rose 3.4 percent in 2018.

If emission reduction efforts fail, the world will be condemned, possibly for centuries, to higher temperatures, rising seas, intensified droughts and flooding, catastrophic storms, and, in many areas, an increased risk of wildfires. The resulting devastation will be economic and political, not just environmental. The Trump administration’s own climate assessment report indicates that by the end of the century climate change could reduce U.S. economic output by as much as 10 percent.

Meanwhile world population, presently 7.6 billion, is expected to reach nearly 10 billion by 2050. Population growth, along with an ever expanding middle class, will put unsustainable pressures on the planet. Wildlife populations have declined on average by 60 percent since 1970, and leading scientists now warn a Sixth Mass Extinction may be underway. Greenhouse gas emissions and the run-off of fertilizers from farms are changing the chemistry and temperature of the oceans. Red tides, like the ones that came ashore in Florida this year, could become common.

Posterity will pay a high price. Climate change and environmental degradation will exacerbate water scarcity and food insecurity, while also increasing the risk of conflict.

Instead of mitigating these risks, the Trump administration is aggravating them by doing its utmost to terminate U.S. support for international family planning assistance. It tried and failed to persuade Congress to wipe out all funding in 2017, but succeeded—by executive action—in terminating U.S. support for the United Nations Population Fund.

Posterity may not long remember the Trump tax cuts, but the women of tomorrow will not forgive or forget what the Trump administration is doing to restrict access to contraception and abortion. Future generations will also lament Trump turning a deaf ear to science and nature. Like a modern day Nero, Trump fiddles while the world around him burns. History will record that no U.S. president has done more to jeopardize people and the planet than Donald J. Trump.

This op-ed by Population Institute President Robert Walker originally ran on January 22, 2019 in Newsweek