An underwater cavern is one of many safe havens that could help restore the marine world | CNN

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The ocean may be our best hope in fighting the climate crisis — but it needs our help.

Due to its vast expanse, the ocean is able to capture at least 25% of the carbon dioxide released by humans into the atmosphere.

The underwater world beneath the waves can trap carbon for thousands, and perhaps even millions, of years. This “blue carbon” is far more efficient than the carbon captured by plants and trees.

But such an impressive capacity can’t be expected to continue without protecting the sea itself, said experts participating in CNN’s Call to Earth Day on Thursday. Scientists suggest preventing fishing and mining in large areas of the ocean, restoring ecosystems like coral reefs and preventing pollution from entering waterways.

If the warming ocean in its current state is able to do its part in saving the planet, a healthier ocean could make an even greater impact, experts believe.

The ocean is full of hope. Just ask the Queen of the Deep herself, Sylvia Earle.

The 87-year-old oceanographer has spent much of her life exploring the ocean and still holds the world record for the deepest untethered walk on the seafloor.

“Every time I go into the water, I see things I’ve never seen before,” she said.

Her Mission Blue program, which supports research and restoration of the ocean, has identified more than 140 marine areas around the world that are critical in revitalizing the ocean. Designated as Hope Spots, these special sites are guarded by local communities and institutions.

Gray nurse sharks might appear menacing with their ragged, needle-like teeth, but a 16-year-old marine conservationist from Port Macquarie in Australia would beg to differ.

“They’re so docile and so curious,” said Shalise Leesfield, who’s working to protect the critically endangered species. “They’re like the Labradors of the sea.”

The slow-moving sharks, which feed on stingrays, urchins and other bottom dwellers, still inhabit Fish Rock, a colorful, coral-filled underwater cavern off the coast of South West Rocks, 40 miles (64 kilometers) up the coast from her home. Thanks to Leesfield, the cave ecosystem has been nominated as a Hope Spot.

She aims to establish a sanctuary zone to ensure that the sharks, which are largely harmless to humans, can continue to breed and survive.

Here comes the sun, and it’s happy to see you.

The NASA Solar Dynamics Observatory captured what appears to be a smile on our star from its vantage point in space. Some social media users thought it resembled the Stay Puft Marshmallow Man from “Ghostbusters,” but the dark patches are actually called coronal holes.

These holes on the sun’s surface can release powerful streams of solar wind, or charged particles, that can reach Earth. And it’s something we might see more of as the sun’s activity ramps up before reaching solar maximum in 2025.

Meanwhile, astronomers spotted a “planet killer” asteroid hiding within the sun’s glare, and it has the potential to cross Earth’s path in the future. The space rock is the largest potentially hazardous asteroid discovered in the past eight years.

“Compostable plastic” isn’t as planet-friendly as it sounds.

The bags, cups, plates and cutlery touted as biodegradable alternatives to harmful single-use plastic items aren’t regulated — and a new study found 60% of products labeled as compostable don’t break down completely.

Instead, keep reusable containers on hand, like mugs or bottles for beverages on the go. And if you see two versions of the same product with different packaging, opt for cardboard over plastic.

Want more ideas on how to minimize your role in the climate crisis and reduce your eco-anxiety? Sign up for CNN’s Life, But Greener limited newsletter series.

The strange tale of an ancient creature was only just beginning when in 1818 fossil collector Mary Anning unearthed an unusual specimen in southwest England.

She found the first complete skeleton of a prehistoric marine reptile named an ichthyosaur, and her discovery contributed to the rise of a young field called paleontology. But the fossil was destroyed during a World War II bombing raid.

A chance find by two researchers revealed two unknown plaster casts of the skeleton tucked away in museum vaults — one in the United States and the other in Germany.

The casts, which preserve precious details of a priceless fossil once thought lost forever, hark back to a time two decades before the word dinosaur was even used.

These intriguing stories will captivate your interest:

— The Hunga Tonga-Hunga Ha’apai underwater volcano eruption in January blasted a towering plume of ash and water up so high, it reached the third layer of Earth’s atmosphere.

— Incredibly rare archaeological evidence uncovered in Finland revealed a child may have been laid to rest alongside a dog 8,000 years ago in a Stone Age burial site.

— The Southern Taurids meteor shower will send bright fireballs blazing across the night sky this weekend. Here’s everything you need to know about how to watch.