Last month was the hottest April on record and the third month in a row with record high temperatures. It’s nearly guaranteed that 2016 will surpass 2015 as another record-breaking year for global temperatures.

April also brought the signing of the Paris climate accord. While this U.N. treaty still needs to be ratified by signatory countries, it marks a major step forward in international cooperation on climate change. The main goal of the U.N. pact:keep our now-unavoidable global temperature increases from surpassing 2 degrees Celsius by 2100.

The big dogs in this fight are the U.S. and China, which together churn out 40% of global greenhouse gases. In China, emissions are still rising and will continue to until 2030. By that year, the country has pledged that 20% of its energy will come from non-fossil fuel sources and its carbon emissions will (finally) start to decline.

China’s still-surging emissions point out the thorniest aspect of the Paris agreement: As countries develop their economies they have, historically, needed more energy and thus burned lots more oil, gas and coal. India, for instance, is home to 17% of the world’s population and currently only produces 6% of global carbon emissions. But the country has ambitious development plans, including bringing electricity to some 300 million people who are without it.

To address this, the Paris accord includes a $100 billion fund to help countries develop in a carbon-neutral way and to prepare for the environmental impacts of climate change (like rising sea levels). But that number is miniscule when compared with the $2.5 trillion in financing India originally sought just for itself. Without international funding, will India be able to, say, quadruple its renewable power generation by 2022?

In the United States, the hurdles are more political in nature. The primary avenue to meeting our treaty obligations is the Clean Power Plan. This set of rules, drafted by the Environmental Protection Agency in 2015, would reduce carbon emissions from U.S. power plants by 32% by 2030. The plan calls for a combination of adding renewable energy sources, improved efficiency, using more natural gas and nuclear power and shutting down coal-fired power plants.

But 29 states and state agencies sued to overturn the Clean Power Plan, saying the EPA had overstepped its regulatory power. The Supreme Court issued a temporary stay in February and sent the case back to the D.C. Circuit Court of Appeals and no decision is expected until after Election Day. The case very likely will go back before the Supreme Court next year, with the deciding vote being whomever is appointed to the current vacancy on the court. Andthat, it seems, will be decided by the next president.

Both Democratic candidates Hillary Clinton and Bernie Sanders support the Paris accord and the Clean Power Plan. To nominee Donald Trump, on the other hand, the Paris accord is just another example of China getting one over on the U.S. “I will be renegotiating those agreements, at a minimum. And at a maximum I may do something else,” the presumptive Republican nominee told Reuters. “But those agreements are one-sided agreements and they are bad for the United States.”

Terrorism, the economy, health care and jobs may be the issues dominating the 2016 election. But it’s climate change where the results in November will reverberate around the globe.