Another important date looms on the calendar this coming week in addition to a national election. On Wednesday, the United States is to become the only nation to officially withdraw from an international pact aimed at slowing climate change.
The exit of the U.S. comes three years to the day after President Donald Trump began the legal process of withdrawing the nation from the 2015 Paris climate accord.
Whether the U.S. exit turns out to be brief or lasting depends on the outcome of the presidential contest. Former Vice President Joe Biden has vowed to rejoin the Paris accord if he is elected.
"For us, it could be a matter of survival," said Carlos Fuller, the lead negotiator for Alliance of Small Island States, a group of 44 islands and low-lying coastal states around the world that act as a bloc at international climate talks.
Sea level rise is already threatening the ability of some island nations in the Pacific, such as Tuvalu and the Marshall Islands, to remain habitable, he said. In the Caribbean, ocean acidification and swelling seas are driving coral reefs toward extinction and imperiling fishing and tourism.
"The next 10 years for us are crucial," Fuller said. "It's imperative that we take action now."
Trump has questioned the science around climate change and looked upon international cooperation as suspect and expensive. Because of the complicated rules of the Paris agreement, the U.S. exit took until the final days of Trump's first term to complete. But his mind has been made up since June 1, 2017, when he announced that the United States would bow out.
The U.S. has not made payments to the Green Climate Fund, which was created to help developing countries adapt to and mitigate the impacts of climate change. It has blocked progress at the Arctic Council, the intergovernmental group that grapples with climate-fueled problems facing governments and indigenous communities in one of the world's fastest-warming regions.
It has teamed up with oil and gas-rich Russia and Saudi Arabia to water down language about the urgency of climate change during international negotiations. It has failed to file, as the accord requires, a biennial accounting of total U.S. greenhouse gas emissions from manmade sources -- and what is being done to reduce them. And the U.S. retreat, many people here and abroad worry, has given license to some other countries to slow their promises to more rapidly cut their emissions.
Moreover, some believe the United States has failed to provide the leadership needed to accelerate the international commitments to reduce greenhouse gas emissions enough to keep the world "well below" 3.6 degrees of warming compared with the late 19th century. That's the threshold beyond which many scientists say the planet will suffer irreversible, catastrophic damage.
Even before Trump became president, the United States looked certain to miss its Paris accord commitment to lower carbon emissions 26% to 28% below 2005 levels by 2025.
"The good news is the rest of the world stayed in the Paris agreement," Pete Ogden, vice president of energy, climate and the environment at the United Nations Foundation, said in an interview. "It shows the buy-in the agreement has even in face of the Trump administration rejecting it."
If Trump wins reelection and keeps the United States out of the international effort to slow climate change, many experts believe that much of the country will move forward without him. Individual states already are pursuing greener energy policies, electric cars are becoming more affordable and sales are increasing, and renewable technologies like wind and solar are getting cheaper and growing rapidly.