A Nobel Prize-winning scientist who stepped down from the National Center for Atmospheric Research in Boulder last year said he did so because the Trump administration had slashed his budget proposals and dissuaded the mere mention of climate change.

Kevin Trenberth ended a 36-year career at the famed climate institution and returned to his native New Zealand, where he continues to research alarming trends of global warming. In an email interview, he wrote that the Trump administration, at the behest of the president, made it increasingly difficult to pursue critical science.

“My ability to do stuff was curtailed,” Trenberth wrote. “I went to 80% to 60% to 40% before retiring and the work I was doing was limited.”

In March of last year, “I left the U.S. because of Trump and the Republicans and the adverse effects on climate funding, among other things. Even before Trump, the Republicans held the chairs of House committees and ‘climate’ could not be mentioned in calls for proposals … (e.g. by NASA and NOAA), which really hurt my work.”

He persisted in the face of a hostile government atmosphere, he wrote, and reported that the five warmest ocean years in human history were the last five years. He didn’t mince words about the cause.

“The warming of the ocean has real consequences,” he concluded. “Ocean heat has exacerbated many of the most significant climate related events in history and contributed to the record number of billion-dollar disasters in the United States.”

Asked to name them, he wrote that “Hurricanes Harvey, Irma and Maria were over $50 billion and Harvey was $150 billion.”

In 2020, storms caused “tremendous damage” with lower dollar costs in poor countries — Fiji, Vietnam and the Philippines, he wrote.

NCAR’s Boulder offices have been largely closed by COVID-19 since March 17, 2020 — “when my retirement party was to have taken place!”

Nevertheless, Trenberth said he and other NCAR scientists, working with colleagues around the world, have managed to conduct groundbreaking research despite the global pandemic, and anti-science rhetoric from the Trump administration..

He credits the Biden administration with attempting to turn the tide but fears Republican efforts to hamstring future climate research.

In any case, the world needs U.S. leadership, he wrote, “but it will be a while before any other country trusts the U.S.”

NCAR opened in 1960 as the first atmospheric research center of the new National Science Foundation. Though it operates as a nonprofit, it depends on federal grant money to exist.

In the United States, the science of atmospheric research began during the Dust Bowl years, when a few curious professors began studying global air movements.

Their knowledge took on strategic value during World War II, when the U.S. needed global weather forecasts to plan massive troop movements from northern Europe to remote South Pacific islands.

After the war, 13 years passed before climate studies began to identify a new potential enemy: Human activity.

The telling research began in 1958 when atmospheric scientist Roger Revelle secured International Geophysical Year money to sample air atop the Mauna Loa volcano in Hawaii.

He and a colleague found a disturbing pattern of yearly carbon dioxide accumulation. In summer months, when tree leaves consumed CO2, concentrations dipped. In the winter they climbed.

On a graph the pattern became clear. They created a zipperlike pattern — up in winter, down in summer — that, slowly but inexorably, showed CO2 levels were rising exponentially.

The implication was obvious. If CO2 levels were increasing atop a high mountain in the middle of the Pacific, they were increasing everywhere.

The basic physical principle was simple. CO2 strikes the ground as ultraviolet light but bounces back as infrared light that fails to escape. For the same reason, CO2 and other greenhouse gases allow tomato growing in winter but make closed car windows lethal in summer.

Revelle’s discovery left ample room for debate. CO2 accounts for less than 1 percent of Earth’s atmosphere.

Why abandon a carbon-fueled economy over a projected 1-degree increase in average global temperature and a few inches of rising sea levels, especially in the face of China’s extraordinary coal-based industrial development?

After all, temperatures rise and fall every day. Rain comes and goes.

In 1988, James Hansen delivered an answer to Congress on a torrid June day. He warned that the first consequence of CO2 accumulation would be extreme weather shifts: Stronger hurricanes coupled with expanding deserts.

At NCAR, Trenberth gradually became convinced that Hansen was right.

He brought an MIT doctorate to the Boulder research center in 1984 and soon stepped onto the world stage as a writer of the world’s most comprehensive climate assessments.

In three reports to the United Nations, the Intergovernmental Panel on Climate Change (IPCC) sounded successively louder alarms about our global future. Trenberth was a lead author of all three.

By 1997, he had become convinced that the modest commitments of the international Kyoto agreement would not stabilize our climate.

In a public television interview, he explained that CO2 had grown to account for 25% of the atmospheric greenhouse gases, second only to natural water vapor.

“Computer models are not perfect by any means,” he acknowledged then, but “the last 10 years have been the warmest years on record,” and glaciers were melting around the world.

Combined with water vapor, greenhouse gases “act like a blanket on planet Earth,” he said.

Worse, the blanket was bound to persist for centuries.

In the air, CO2 molecules live for 100 to 200 years. As a result, “projected rates of change in the next 100 years are much greater than anything we’ve seen in nature,” he said.

That proved to be an understatement. In Houston, for example, Hurricane Harvey became its third “500-year storm” in three years.

In February, the other extreme struck home. One Arctic blast overwhelmed the faulty Texas power grid and deprived millions of electricity, heat and water, leaving grocery shelves bare.

In hindsight, Trenberth wrote, “IPCC is conservative.” Reality had outpaced its reports, which depended on a consensus among more than 180 nations.

Nevertheless, its scientists were rewarded for their efforts with the world’s highest honor: the Nobel Peace Prize.

Sharing that accolade was one of professor Revelle’s star student, a man who would spend his life clamoring for lower greenhouse gas emissions: Former Vice President Al Gore.

Skeptics greeted the prestigious prize with derision. The greenhouse gas debate raged on amid growing signs of disaster.

COVID shuttered NCAR’s doors but not its lightning fast computer system.

The newest supercomputers function at teraflops (10 to the 12th power) or even petraflops (10 to the 15th power) per second.

To put that in perspective, it would take a human performing one calculation per second 31,688 years to reach one teraflop, 31 million years per petraflop.

NCAR scientists collaborate with colleagues around the world in studies that aim to tackle the most complicated, and perhaps the most important, puzzle on Earth.

Their long-range forecasts must take into account greenhouse gas effects on land, air, water, vegetation and above all, human behavior.

The 2016 Paris climate agreement, signed by nearly 200 nations, acknowledges that three centuries of industrial development, a mere blink in geologic time, have changed our climate already. It commits each nation to help limit warming to less than 3.6 degrees Fahrenheit in the 21st century.

Despite COVID and budget cuts, NCAR scientists keep publishing groundbreaking reports with ominous warnings.

Trenberth reported his findings about rapidly warming ocean waters with a Chinese scientist who took different measurements but reached the same conclusion.

Worse, he found that the warm waters rest atop the ocean as a separate layer, depriving sea life below of nutrients.

As climate shifts devastate coastal areas with record hurricane seasons, Colorado faces the opposite threat: Drought and wildfires.

Last year brought the worst fire season on record, topping the fire seasons of 2018 and 2002.

In February, a new NCAR study reached a worrisome conclusion about long-term drought prospects. It found that winter snow melt and summer thunderstorms needed to replenish the Colorado River, the aorta of the West, could be absorbed by expanses of parched ground instead.

In Colorado, far from ocean waters, people face a different climate disaster: yearly wildfires.

Trenberth said shifts in Pacific currents, known as El Niño and La Niña, greatly influence moisture across Western states and can bring drought relief in some years.

But he also offered this sobering statistic: Our two worst fire seasons on record were 2020, followed by 2018.

At West Metro, Ronda Scholting welcomed a much needed March blizzard, but fears one warm spring stretch will leave her district dry as ever.

Colorado no longer has a fire season, she said.

“It’s year round.”

This year the fire season started in mid-winter.

A pair of wildfires erupted in Bear Lake Park and Cherry Creek State Park on Feb. 7, Super Bowl Sunday.

The Bear Lake fire, just east of Morrison, was spotted at 1:30 p.m. and raged out of control in half an hour. 

Ranger Luke Wilson said howling gusts from the foothills blew flames and smoke clouds across the park to the Fox Hollow golf course.

By 3 p.m., an hour before the football game, police were going door to door in the Fox Hollow neighborhood, ordering people to get out immediately.

Homeowner Barbara Carlson barely had time to ask, “What are the things that are irreplaceable or very expensive?”

She grabbed family pictures and medicine for their arthritic chocolate lab Shiloh. Her husband fled with his hunting and fishing gear. Their nephew, who had come to seek work, got out with his new shirts and shoes.

The blaze brought firefighters from 11 agencies who managed to douse it without losing a single home. They spent two days putting out the hot spots.

The Super Bowl fire blackened nearly a square mile of ground from the park to the golf course but spared its moist greens, leaving a bizarre polka-dotted landscape in its wake.

“There’s going to be a bad fire season every year,” ranger Wilson said glumly. “It’s never going to end.”

On the positive side, he mused, spring should bring a green carpet of new growth.

A month later, the cause of the fire remains unsolved. Tatters of windblown police tape, however, suggest someone lit it about 50 yards south of Morrison Road, just inside the park’s barbed wire boundary.

It’s been a strange winter. While Colorado’s high mountains lie buried in avalanche-deep snow, the foothills stand bone dry.

Sixty-degree weather melted a much-needed February snowstorm, leaving only dandruffs of snow on the foothills’ north slopes.

In years past, March has been Colorado’s snowiest month. So far, this March has been exceptionally warm, until the recent snowstorm that dumped more than two feet of snow in Denver metro areas.

Last weekend’s snowstorm gave firefighters reasons for cautious optimism.

“Obviously, this helps in the short run,” Scholting said. Still, “if we get nothing in April and May, it’s going to be extremely dry.”

At West Metro Fire Rescue, the lead agency at the Bear Creek Park blaze, public information officer Ronda Scholting said her entire district remains in drought or extreme drought.

By now, its firefighters have battled wildfires in every month on the calendar.

“There’s really no fire season in Colorado anymore,” she said. “It’s year round.”