President Biden signed an executive order to have the country reenter the Paris Climate Agreement, less than four months after formally withdrawing.

President Biden has set his sights on more than 100 Trump administration environmental rollbacks as well as plans to rejoin the international climate accord.

Overwhelmed sewers. Flooded streets. Deadly heat waves. Baltimore is one of many American cities where the costs of climate change far exceed local resources. Should oil companies pay?

Lou Gehrig's disease can take months to diagnose, then rapidly incapacitate patients, leaving many families bankrupt before disability payments and Medicare kick in. A recent law aims to change that.

Elizabeth Blackwell was the first woman in America to earn her medical degree. Her sister Emily followed in her footsteps. Janice Nimura tells the story of the "complicated, prickly" trailblazers.

The test was for NASA's Space Launch System, a successor to the retired Space Shuttle program. It takes eight minutes to generate the power needed to get to space, and ultimately to the moon.

As states suddenly expand the categories of people eligible for the first scarce shipments of vaccine, who will be watching to make sure those hit hardest by the pandemic aren't left behind?

The change means that doctors will no longer need a special federal waiver in order to prescribe buprenorphine, a medication to treat opioid use disorder.

Each day, we breathe about 22,000 times--and all that time we smell. Scent historian Caro Verbeek recreates scents of the past. She says, just like music and art, smell is a part of our heritage.

As Americans stayed home during the pandemic, cars and planes produced less heat-trapping emissions. But the effect is only temporary.

Starting Jan. 26, airlines will only allow people to board if they provide documentation that they tested negative in the preceding three days or have recovered from the disease.

It takes time after vaccination for immunity to the virus to build up, and no vaccine is 100% effective. Plus, scientists don't yet know if the vaccine stops viral spread. Here's what's known so far.

A hundred years ago, a world war and a pandemic wreaked havoc on baseball and other industries. But pent-up demand helped them come roaring back.

Gorillas at the San Diego Zoo Safari Park developed a cough last week. The apes were tested and found to have the virus. It may have come through a human staffer, despite precautions.

The House speaker told colleagues she had spoken with the chairman of the Joint Chiefs of Staff about keeping the nuclear codes from an "unhinged President."