Christopher Joyce

Some of the world's top climate scientists have concluded that global warming is likely to reach dangerous levels unless new technologies are developed to remove greenhouse gases from the atmosphere.

The United Nations' Intergovernmental Panel on Climate Change (IPCC) says pledges from the world's governments to reduce greenhouse gases, made in Paris in 2015, aren't enough to keep global warming from rising more than 1.5 degrees Celsius (2.7 degrees F) above pre-industrial temperatures.

Conservationists have developed a new high-tech strategy to trace the cartels that smuggle much of the illegal ivory around the world — by using DNA to track ivory back to specific ports.

Biologist Samuel Wasser from the University of Washington is behind the effort. He notes that while poaching in Africa has dipped recently, too many elephants are still dying.

"Right now we're estimating that there are about 40,000 elephants being killed every year," he says, "and there are only 400,000 left in Africa. So that's a tenth of the population a year."

Scientists working in South Africa say they've found the earliest known drawing. It was dug up in a cave where early humans apparently lived for thousands of years and left behind numerous artifacts.

A warming world could eventually make some of our most familiar ecosystems — deciduous forests, grasslands, Arctic tundra — unrecognizable.

That's the conclusion of a team of more than 40 scientists who took a novel approach to predicting the effects of how human-caused global warming will alter ecosystems. They looked about 20,000 years back in time.

More Americans die from the effects of heat than of any other form of severe weather, and this summer has seen one heat wave after another. Some places in the U.S. and elsewhere have recorded their highest temperatures ever. In fact, the average temperature around the planet over the past four years has been the highest ever recorded, and nine of the 10 hottest years were all in this century. (The other was 1998.)

A huge pack of floating ice along the northern Greenland coastline is breaking up and drifting apart into the Arctic Ocean — another consequence, scientists say, of global warming caused by the buildup of greenhouse gases in the atmosphere.

"We've never seen anything this large in terms of an opening north of Greenland," says polar scientist Ted Scambos of the National Snow and Ice Data Center, which collaborates with the National Oceanic and Atmospheric Administration.

Plastic trash is littering the land and fouling rivers and oceans. But what we can see is only a small fraction of what's out there.

Since modern plastic was first mass-produced, 8 billion tons have been manufactured. And when it's thrown away, it doesn't just disappear. Much of it crumbles into small pieces.

When a huge floating gyre of plastic waste was discovered in the Pacific in the late 1980s, people were shocked. When whales died and washed ashore with stomachs full of plastic, people were horrified. When photographs of beaches under knee-deep carpets of plastic trash were published, people were disgusted.

Though some of it came from ships, most, presumably, was from land. But how much was coming from where?

Scientists have uncovered a pit of human bones at a Civil War battlefield in Virginia. The remains are the amputated limbs of wounded Union soldiers.

It's the first "limb pit" from a Civil War battlefield to be excavated, and experts say it opens a new window on what is often overlooked in Civil War history: the aftermath of battle, the agony of survivors and the trials of early combat surgeons.

For the first time, scientists have videotaped sharks traveling a 500-mile-long "shark highway" in the Pacific, and they plan to turn it into a protected wildlife corridor in the ocean.

There's going to be a changing of the guard in space. On Tuesday, NASA is launching two new satellites, collectively called GRACE, to replace two that have been retired after 16 years in orbit.

The oceans are getting warmer and fish are noticing. Many that live along U.S. coastlines are moving to cooler water. New research predicts that will continue, with potentially serious consequences for the fishing industry.

Hurricane Harvey, which devastated South Texas last August, was powered by what scientists say were the highest ocean temperatures they've ever seen in the Gulf of Mexico.

When it comes to motherhood, at least if you're a fish, big is better. Bigger fish produce more far more offspring pound for pound than smaller fish. And that can mean more on your plate.

The new research comes from a team in Australia and Panama and reinforces fishing practices that protect larger fish as well as marine protected areas, which are like fish "sanctuaries" in the ocean.

New research suggests that global warming could cause temperature swings to get unusually extreme. And the regions where the biggest swings will occur are among the poorest in the world — and the least responsible for the greenhouse gas emissions that cause global warming.

Climate scientists already know that as the planet warms, there's a bigger chance of extreme weather: bigger hurricanes, for example, or heavier rainfall.

Tiny particles of plastic are showing up all over the world, floating in the ocean, buried in soil, in food and even in beer. Now there's new research that's found microplastics in fertilizer — organic fertilizer from food waste, in fact.

Collecting food waste to make fertilizer is a big deal in parts of Europe and is catching on in the U.S. But Ruth Freitag, a chemist at the University of Bayreuth in Germany, says there's a problem.

A lot of smart people spend a lot of time trying to predict how much oil and gas is going to come out of the ground in the future.

Lately, they've been getting it wrong.

"Unpredictability, measured as the frequency of extreme errors in ... projections, has increased in the most recent decade," according to an unusual new study by a team at Carnegie Mellon University that found analysts are getting worse at predicting both how much oil and gas will be produced and how much Americans will need.

Tens of thousands of years ago, the first artists painted images on the walls of caves. They collected, painted and ground holes in shells, presumably to wear. It was the very first art, created by what we call "modern humans," or Homo sapiens.

Animals that live in the ocean communicate with sound — humpback whales, for example. But these voices could soon be drowned out by powerful sonic booms from vessels searching for oil and gas.

Millions of tons of plastic waste end up in the ocean every year. And the trash stays there: Whether it's grocery bags or water bottles or kids' toys, plastic is practically indestructible.

Now marine scientists have discovered that it's killing coral reefs.

A new study based on four years of diving on 159 reefs in the Pacific shows that reefs in four countries — Australia, Thailand, Indonesia and Myanmar — are heavily contaminated with plastic. It clings to the coral, especially branching coral. And where it clings, it sickens or kills.

A new study suggests that the polar jet stream has been fluctuating more than normal as it passes over the parts of the Northern Hemisphere, and that's affecting weather in Europe and North America.

Before it got cold this winter, it was warm. Very warm. In fact, new data out Monday shows 2017 was the third warmest year recorded in the lower 48 states.

And it was also a smackdown year for weather disasters: 16 weather events each broke the billion-dollar barrier.

First, the heat. Last year was 2.6 degrees F warmer than the average year during the 20th century.

The Arctic is a huge, icy cap on the planet that acts like a global air conditioner. But the air conditioner is breaking down, according to scientists who issued a grim "report card" on the Arctic on Tuesday.

They say the North Pole continues to warm at an alarming pace — twice the rate as the rest of the planet, on average. This year was the Arctic's second-warmest in at least 1,500 years, after 2016.

The world's oceans are rising. Over the past century, they're up an average of about eight inches. But the seas are rising more in some places than others. And scientists are now finding that how much sea level rises in, say, New York City, has a lot to do with exactly where the ice is melting.

A warming climate is melting a lot of glaciers and ice sheets on land. That means more water rolling down into the oceans.

But the oceans are not like a bathtub. The water doesn't rise uniformly.

After Hurricane Harvey, some Texas residents, politicians and scientists are wondering whether the whole U.S. system for predicting floods is any good.

The storm's deluge flooded parts of southeast Texas that had rarely, or never, been underwater before. Some areas got more than 50 inches of rain in a few days. "When the numbers started coming in it was a little scary," says Matt Zeve, the director of operations for the Harris County Flood Control District, which includes Houston.