KENSINGTON, Maryland — The world cut its daily carbon dioxide emissions by 17% at the peak of the pandemic shutdown last month, a new study found.

But with life and heat-trapping gas levels inching back toward normal, the brief pollution break will likely be "a drop in the ocean" when it comes to climate change, scientists said.

In their study of carbon dioxide emissions during the coronavirus pandemic, an international team of scientists calculated that pollution levels are heading back up — and for the year will end up between 4% and 7% lower than 2019 levels. That's still the biggest annual drop in carbon emissions since World War II.

It'll be 7% if the strictest lockdown rules remain all year long across much of the globe, 4% if they are lifted soon.