60 Minutes climate change archive: What climate impacts

This week on 60 Minutes, Lesley Stahl reports that climate change is altering some of the world's prime wine-growing regions. Extreme weather episodes are upending the practices and economics of winemaking - and in some cases, changing the taste of the wine itself - in Old World and New World vineyards alike.

It is the broadcast's latest report to detail the impact of a warming planet. From flooded cities to parched rivers, melting glaciers to scorched forests, 60 Minutes continues to cover all the ways a changing climate is transforming life on Earth. Here, a look back at some of them.

SCIENTISTS AND THE POLITICS OF CLIMATE CHANGE

"This is a scientific consensus. There's about as much scientific consensus about human-caused climate change as there is about gravity." - Michael Mann

In 2006, government scientist James Hansen took a risk by appearing on 60 Minutes. Then the director of the NASA Goddard Institute for Space Studies, Hansen is arguably the world's leading researcher on global warming and has been called the "father" of climate change science.

He told correspondent Scott Pelley that the Bush administration was restricting who he can talk to and editing what he can say about how human activity has changed the climate. NASA would only permit him to speak with 60 Minutes if a NASA representative taped the interview.

Politicians, Hansen said, were attempting to rewrite the science.

"Should we be simply doing our science and reporting it rigorously, or to what degree the administration in power has the right to assume that you should be a spokesman for the administration?" Hansen said. "I tried to be a straight scientist, doing the science and reporting it as best I can."

 Pelley spoke with Hansen again in 2020, a year that saw the largest wildfires in California history and twice the usual number of tropical cyclones. The highest temperature ever recorded scorched Earth that August.

"The physics is quite simple," Hansen told Pelley in 2020. "As you add more greenhouse gases to the atmosphere, you increase the heating of the surface. So, at the times and places where it's dry, you get more extreme droughts. The fire seasons become longer. The fires burn hotter. But at the times and places where it's wet, you get more evaporation of the water. And you get warmer, moist air, which provides greater rainfall. And it's the fuel for storms."

Still, in a press conference with California firefighters and officials, President Donald Trump dismissed questions on climate change by saying, without evidence, that the climate will cool. "I don't think science knows, actually," Trump said.

"This is a scientific consensus," said geophysicist Michael Mann, the director of the Earth System Science Center at Penn State and a member of the National Academy of Sciences. "There's about as much scientific consensus about human-caused climate change as there is about gravity."

Mann told Pelley the warming can be stopped. Oceans and forests would begin to absorb excess carbon in a matter of years if emissions - principally from coal-fired power plants - are reduced close to zero.

Hansen believes the way to do that is for governments to tax cheap fossil fuels to make them more expensive than clean alternatives. The consequences without it, he warned, are too terrible.

"The worst visions that Hollywood has given us of dystopian futures are real possible futures if we don't act on this problem," he said, "the greatest crisis that we face as a civilization."

MELTING GLACIERS

In 2006, correspondent Scott Pelley traveled to the Arctic to see the impact of climate change up close. He spoke with Bob Corell, an American scientist who led 300 of his colleagues from eight nations in a study called the Arctic Climate Impact Assessment.

The study's findings offered what Corell called a "global warning:" Seas are rising, hurricanes are becoming more powerful, and polar bears may be headed toward extinction.

"This is a bellwether, a barometer, as some people call it, the canary in the mine," Corell told Pelley in 2006. "The warning that things are coming. In 10 years, here, in the Arctic, we see what the rest of the planet will see in 25 or 30 years from now."

Pelley's report also explored how much of this transformation is due to Earth's naturally changing climate and how much is man's doing. According to Paul Mayewski, director of the Climate Change Institute at the University of Maine, the answer is frozen in the Arctic's glaciers. As it freezes, ice captures everything in the air, so the Arctic's ice has captured an atmospheric record that covers half a million years.

According to Mayewski, Arctic ice cores, cylinders of ice drilled from glaciers, indicate carbon dioxide levels are higher than they have been in hundreds of thousands - if not millions - of years.

"It all points to something that has changed and something that has impacted the system which wasn't doing it more than 100 years ago and we know exactly what it is," Mayewski said. "It's human activity."

 Ten years after Pelley reported from the Arctic, correspondent Sharyn Alfonsi visited Greenland's Petermann Glacier. It is one of the largest glaciers in the Arctic Circle - and one that has experienced significant melting.

Alfonsi spoke with scientists who were drawn to this remote sliver of Greenland, in part, by satellite images that show the glacier had receded by 20 miles in five years. The team was trying to understand how the oceans interact with and melt the ice, and to predict how in the future that melting might change.

Alfonsi spoke with Peter Demenocal, a paleoclimatologist at Columbia University who studies ice cores. He told Alfonsi that the cores pulled from Petermann Glacier are filling in a crucial piece of the climate change puzzle.

"We're not just saying that climate in the Arctic is changing," Demenocal said. "It's changing at an accelerating rate. So basically it means it's starting to melt but it's melting at a faster and faster clip. So anyone who knows what it's like to fall off a cliff, that's what it's doing."

RAGING FIRES

60 Minutes began covering a new era of immensely destructive wildfires in 2007. As correspondent Scott Pelley reported, "It appears we're living in a new age of megafires, forest infernos 10 times bigger than the fires we're used to seeing."

To find out why, Pelley interviewed Tom Boatner, who after 30 years on the fire line, had become the chief of fire operations for the federal government. Boatner told Pelley that fires of the size and intensity burning in 2007 would have been extremely rare 15 or 20 years before.

"Ten years ago, if you had a 100,000-acre fire, you were talking about a huge fire," Boatner said. "And if we had one or two of those a year, that was probably unusual. Now, we talk about 200,000-acre fires like it's just another day at the office. It's been a huge change."

One culprit, Pelley reported, is climate change. He spoke with Tom Swetnam, one of the world's leading fire ecologists. Swetnam and his colleagues had just published their findings showing that climate change had increased temperatures in the western U.S. by one degree, and that has caused four times more fires.

"As the spring is arriving earlier because of warming conditions, the snow on these high mountain areas is melting and running off," Swetnam told Pelley. "The log and the branches and the tree needles all can dry out more quickly and have a longer time period to be dry. And so there's a longer time period and opportunity for fires to start."

 Another recent example of megafires were the infernos that engulfed Australia from late 2019 to early 2020. While bush fires have always burned in Australia, the scale of the 2019-2020 fires was unprecedented.

As 60 Minutes contributor Holly Williams reported in February 2020, the fires impacted the entire country, scorching a reported 27 million acres, killing an estimated one billion animals, and causing poor air quality in cities throughout Australia.

Scientists blame climate change for the country's extended fire season, saying the environment has become increasingly hot and dry at an alarming rate.

"I think this summer has been a real wake-up call for most Australians," Joelle Gergis, a climate scientist at the Australian National University and a lead author of a United Nations report on climate change, told Williams in 2020. "And myself as a climate scientist, seeing the extreme level of heat and the bushfires and the drought conditions playing out so catastrophically has been, I think, a wakeup call to the world."

SEVERE FLOODING

Before climate scientists worried about Australia burning, they warned that Venice, Italy, is drowning.

As John Dickerson reported in January 2020, Venice's periodic floods have become more threatening and more frequent. The prior November, a sudden storm surge overwhelmed nearly 90 percent of the city. Climate scientists say what happened in Venice is a warning to the world of what's to come - and not just in Italy.

"The rest of the world should take the message that this is what the situation is going to look like in many places that they live in," said Michael Oppenheimer, a professor of geosciences at Princeton University and a lead author of a landmark report for the United Nations on climate change. "Venice is just, you know, as everybody says, the canary in the coal mine. It's happening there now."

Climate change, Oppenheimer said, is the major reason for increasingly heavy flooding across the globe. Sea levels are rising, he told Dickerson, and the rise is accelerating. American coastal cities at risk for severe flooding include Los Angeles, San Diego, Key West, Miami, Jacksonville, Savannah, and Honolulu.

"So by the year 2050, which is only thirty years into the future, many places around the world, including in the U.S., are going to experience their historical once-in-a-hundred-year flood level once a year or more frequently," Oppenheimer said. "Let me repeat that. An event that used to cause severe flooding once a century, we're going to get that same water level once a year."

PARCHED RIVERS

While some cities across the globe are at risk of severe flooding, others are in danger of running out of water. In 2021, correspondent Bill Whitaker reported on the Colorado River, where water levels had dropped so low that the federal government declared an official shortage for the first time.

The river runs more than 1,400 miles and serves more than 40 million people who live in its vast basin. But the Colorado has been running dry due to a 20-year drought - as dry as any period in twelve hundred years.

"It's a signal of the long-term problem we've been seeing since the year 2000, which is climate change is reducing the flows of the Colorado significantly," said Brad Udall, a climate scientist at Colorado State University.

The Colorado River's waters irrigate farms that produce 90 percent of the country's winter greens. But it takes more than two-thirds of the river to produce the harvest. With the Colorado River's lake system's levels dropping, Arizona farmers like Waylon Wuertz fear their fertile fields could become desert again.

"You're going to see drastic cuts, a drastic change of what next year has to bring," Wuertz told Whitaker. "And for my particular family farm, we're doing all that we can to keep it going. But I have a feeling it's just a matter of time before none of this exists."

MORE INTENSE HURRICANES

When Hurricane Dorian slammed into the northern Bahamas in 2019, it was the fifth Category 5 Atlantic hurricane in just the last three years. Before that, there hadn't been a single storm of that intensity in nearly a decade. As Bill Whitaker reported in 2020, there is a growing consensus among scientists that climate change is what is making these hurricanes stronger and more destructive.

In the heart of what has come to be known as Hurricane Alley, the Bahamas have found something that can help its islands survive future severe hurricanes - a solar array.

When intense storms like Dorian blow through, they often knock out the electricity by destroying substations and knocking over utility poles. But rather than using diesel-fueled generating stations on each inhabited island, solar arrays with battery storage provide electricity when the sun does not shine. They can either feed electricity into the larger grid or operate independently to power a single facility or a neighborhood.

Still, Bahamian Prime Minister Hubert Minnis would prefer it if larger countries took action to lessen the warming climate that contributes to more powerful storms in the first place.

"First World nations make the greatest contribution to climate change," Minnis told Whitaker in the report. "They are the ones responsible for the changes that we see - the increase in velocity and ferocity of the hurricanes and the typhoons that we see today. But we're the innocent victim. We're the ones that are being impacted by what you have created."