March 2026 set records in California for its unusual heat, early snowmelt and lack of precipitation. Those are the type of conditions climate scientists have been modeling for decades.
In 1998, Dr. Michael Mann and his colleagues published the renowned “hockey stick” curve, which demonstrated that the warming of the planet over the last century is unprecedented as far back as a thousand years. It revealed the reality of human caused warming in the industrial age.
That research and those scientists came under immediate attack by the most powerful forces in the world, and it continues. Recent investigations are confirming the ongoing increase in greenhouse gases, and the cascading impacts of a warming earth.
The hockey stick is perhaps the most iconic graphic symbol of climate change in our age. It represents the amount of carbon dioxide in Earth’s atmosphere. Mann and his fellow researchers presented their data in a way that dramatically illustrated the reality of human caused global warming. Now, he emphasizes, climate indicators are worse than when that study came out 28 years ago.
“The hockey stick has gotten sharper and longer. What do I mean by that? You could think of it as a handle and a blade,” Dr. Mann shared with the Community Alliance after a speech at Fresno City College.
“The handle was like the relatively flat trend in temperatures prior to the industrial revolution. Not much was happening on the long handle; the blade is the sharp warming of the past century. That coincides with the industrial revolution with fossil fuel burning and the increase in carbon pollution in the atmosphere. And there’s a causal connection between those two things. The rapid warming is a product of our burning of fossil fuels and the hockey stick laid that bare.”
Evidence is all around us. According to the National Oceanic and Atmospheric Administration, we are living in the hottest decade on record. By 2024, Earth’s temperature was 2.6 degrees Fahrenheit above the pre-industrial average.
NASA reports that the ocean is getting warmer. The top 100 meters has warmed by two-thirds of a degree Fahrenheit since 1969.
Ice sheets are melting. Glaciers are retreating. Greenland is losing about 280 billion tons of ice per year, while Antarctica loses roughly 150 billion tons annually. Snow cover is decreasing globally.
“What’s happened since is that other scientists have extended that handle farther back in time, in some studies by tens of thousands of years.” Dr. Mann said.
“And so that handle has gotten longer and the blade has gotten longer, which is to say that in the last two and a half decades, the warming has continued unabated. So that blade, that sharp upturn has gotten longer and longer. The warming has continued on and it will continue until we stop burning fossil fuels.”
Consensus among the scientific community has established a red line that should not be crossed. An additional temperature increase beyond 1.5 degrees Celsius, or 2.7 degrees Fahrenheit is entering dangerous territory.
According to the United Nations, doing so will trigger climate tipping points and accelerate catastrophic and irreversible climate change impacts. Dr. Mann explains why we should avoid that benchmark.
“That is often specified as a level of dangerous interference, which is to say there are lots of bad things we’re already seeing, but we’ll see even worse things if we warm the planet that much.
“It’s not a cliff. You don’t go off a cliff, which is to say if we do breach that threshold, it’s still much better to keep warming below two degrees Celsius. And it’s still much better to keep warming below two and a half.
“Every bit of carbon that we burn makes things worse. Every bit of carbon we don’t burn makes us better off. And so, it’s about getting off this fossil fuel highway as quickly as we can.”
Dr. Mann says the message is pretty clear. If we want to prevent the continued sharpening of the blade on that hockey stick graph, and all of the detrimental consequences that are coming with that, people have to act now.
“The window of opportunity to do that is closing. With each passing year where our carbon emissions remain anywhere close to where they are right now, we are eroding what we call the budget—the amount of carbon that we have left to burn and still keep warming below that critical level of one and a half Celsius. With a few more years of business as usual where we don’t dramatically lower carbon emissions, we will burn through that budget and we will see that one and a half Celsius, three-degree Fahrenheit warming.”
Burning through the carbon budget, climate models predict, is expected to result in hotter heatwaves, more rapidly rising seas, biodiversity loss, extreme weather disasters, water stress and food insecurity.
Even as the Earth atmosphere approaches that catastrophic scenario, climate science and scientists are under siege in America. That’s the message that Dr. Mann wants the public to take seriously.
He, along with pediatrician and tropical disease expert Dr. Peter Hotez are taking the fight to the public with a new book entitled Science Under Siege. They detail the attack on climate and medical science through massively funded disinformation campaigns by the oil industry and its political allies for more than two decades.
They have been at the forefront of research, and targets of attacks on their science and themselves by powerful forces. They name it the five P’s: plutocrats, like the Koch brothers and Elon Musk; petrostates like Saudi Arabia, Russia, even the United States; and professional anti-science advocates along with company propagandists.
Dr. Mann says they all flood the zone with misinformation and disinformation. The fifth P, he says, is the press.
“You’ve got the press, I mean the media of course. And it isn’t just the right-wing press—the Murdoch media empire, Fox news, New York Post, Wall Street Journal editorial pages. It’s even the New York Times, the Washington Post, as we detail in the book, often engaged in what we call ‘performative neutrality’ where they platform anti-science as if it deserves equal space with what actual science has to say. It’s all in the name of balance and it has not served us well.”
Dr. Mann concludes that all of those forces have combined in the perfect storm that has landed us where we are right now when it comes to the climate crisis, pandemics like Covid-19, or other major challenges. Dr. Mann recalls that the assaults on his research and his person have been coming for a long time.
“In the late 1990s, my co-authors and I published the now well-known hockey stick curve, which demonstrated that the warming of the planet over the last century is unprecedented. The profound nature of the impact our fossil fuel dependence is having. And that made me a target for bad actors doing the bidding of the fossil fuel industry. And I found myself under attack. So, if they had left me alone, I’d probably still be in a computer lab crunching numbers.”
Instead, Dr. Mann became a public voice explaining the dangers of climate change. Now, his mission is even more urgent. The second Trump administration and Project 2025 have prompted de-funding of scientists, and the dismantling of the very research lab that first identified human generated global warming.
“It’s very interesting to look at what their main targets have been when it comes to sort of the climate science community. They’ve gone after the NASA Goddard Institute for Space Studies in New York, the former director of which was James Hansen, who first warmed the public that climate change was here back in the late 1980s. And he was an outspoken advocate for climate action.”
The damage has continued with the breaking up of the National Atmospheric Research Center in Colorado that did early climate modeling. The federal government is also eliminating funding the essential Mauna Loa observatory in Hawaii. That will shut down decades of carbon dioxide measurements that Dr. Mann says are crucial for keeping track of the buildup of greenhouse gases.
But there is still an opportunity to blunt the attacks. Dr. Mann sees the Trump administration as losing political capital, and he is hopeful that the mid-term elections will result in a change in Congress that will help thwart even more damage to the nation’s science institutions.
“This is personal. The fossil fuel interests, the front groups that have supported them, the plutocrats behind them, for decades seeing climate scientists as the enemy. They really want to go right to the heart of the scientific community.”
