For Earth Day 2024, experts are spreading optimism – not doom. Here's why.

Climate change may still be an existential threat to humanity, but as Earth Day 2024 rolls around on Monday, some of the people most concerned about the planet aren't peddling doom – they're spreading optimism.

There's plenty to feel good about, they say: Huge strides towards fighting climate change, decades of work that have led to other environmental disasters being averted – and the reality that hope can help fuel the actions needed to keep tackling the climate crisis.

“People assume that in the 50 years since the first Earth Day we’ve made no progress. That we’re in a worse position now than we were in the 1970s, that there’s no point to environmental action,” said Hannah Ritchie, a senior researcher at the University of Oxford in the United Kingdom who studies sustainability in relation to climate change.

Quite the opposite is true. Climate-friendly advances that would have seemed impossible even 10 years ago are now commonplace. And three times in the past 50 years humanity has faced – and fixed – massive, man-made global environmental issues.

This Earth Day, some climate scientists think climate change could be added to the list.

That reality is still a long way off, but we've made more progress than you might think. It's as if humanity has to climb the world’s tallest mountain, said Katharine Hayhoe, chief scientist of The Nature Conservancy and a distinguished professor of climate science at Texas Tech University.

Wind and solar power are the cheapest electricity on the planet. Heat pumps come up in most heating and cooling discussions. Electric cars are now mainstream.

Monday brings even more funding for climate-friendly causes, with the Biden administration announcing $7 billion in grants to provide solar power to over 900,000 homes in low-income and disadvantaged communities. The White House said the president’s actions would save more than $350 million in electricity costs annually – roughly $400 per household – over the next 25 years.

“It's like climbing the world's tallest mountain," Hayhoe said. "You walk and walk and you climb and climb and the top seems like it's never getting closer. But when you turn around, you realize how far you've come.”

Even Al Gore, former senator and vice president who famously began warning Americans about global warming in 1981, feels a little positive.

In March, he acknowledged to USA TODAY that things aren’t moving fast enough but said, “We’re gaining on this, we’re gaining momentum and soon we'll be gaining on the crisis itself.”

Three huge climate wins in 50 years

Humanity has already had some amazing wins when it comes to other big, seemingly intractable environmental issues.

Take DDT, a pesticide originally seen as a miracle in the fight against mosquitoes and other vermin when it was first introduced in the 1940s. It wasn't until the late 1950s that scientists connected the dots between declining bird populations and the new wonder chemical. DDT thinned eggshells so that nesting mothers crushed their own babies – leading many species, including the bald eagle, to the brink of extinction.

But DDT was banned in 1972 and by 2007 bald eagles had made such a comeback they were removed from the Endangered Species list.

Or look up at the sky and ponder the ozone layer that protects us from ultraviolet radiation. In the early 1980s scientists first saw that a hole had developed in that critically protective layer of the atmosphere. Without it, fields would burn and the outdoors would be unsurvivable. Despite the costs and the immensity of the problem, nations around the world signed the Montreal Protocol, phasing out the chlorofluorocarbons that caused the hole. Today, the ozone is repairing itself and is expected to return to 1980 levels by 2060.

Then there was acid rain, the byproduct of burning sulfur-laced coal. Beginning in the 1950s, it killed forests and life in lakes and streams across broad swaths of the northeast, with public awareness of its dangers growing in the 1970s. The Clean Air Act of 1990 helped limit sulfur emissions and levels began to fall.

Global CO2 emissions could peak next year

It's important to remember that history when considering the grim news about carbon dioxide levels in Earth's atmosphere, the root cause of global warming.

Last year they hit the highest point in human history, 420 parts per million. That’s up from 280 parts per million before the Industrial Revolution. In that time, global temperatures have risen by about 2 degrees.

But there’s something else happening that doesn’t get as much notice but is very hopeful. Experts – including the International Energy Agency – say that global carbon dioxide emissions will probably peak next year and certainly by 2030, using a scenario based on current policy settings.

That means 2023 was very likely the year with the highest greenhouse gas emissions ever and the numbers will only go down from here.

While that won’t make up for all the CO2 that has been pumped into the Earth’s atmosphere since the mid-1700s, it’s an important milestone and shows how the energy shift is already well underway.

Last year:On Earth Day, scientists tell us what 2050 could be like. Their answers might surprise you.

“The transition to clean energy is happening worldwide and it’s unstoppable,” IEA Executive Director Fatih Birol said last year. “It’s not a question of ‘if’, it’s just a matter of ‘how soon.’”

That said, current emission levels are a third higher than they needed to be to limit global warming to 2.7 degrees. So global per capita emissions still must come down significantly. But progress is being made, progress that's not always apparent to the general public, said Ritchie.

Clean energy is now the cheapest energy

That progress is being aided by more good news. Clean energy, from solar and wind, has gotten very cheap much faster than many climate experts ever hoped.

“The world is fundamentally in a different place from what it was in 1970. Even just a decade ago we were in a completely different position,” said Ritchie, whose book "Not the End of the World: How We Can Be the First Generation to Build a Sustainable Planet," came out in January.

Today, solar, wind and battery power are dramatically less expensive than they were even 10 years ago. In 2023, electricity from wind and solar was significantly less expensive than from coal, nuclear and natural gas.

The unsubsidized cost of wind power has dropped 66% since 2009, while the cost of unsubsidized solar has fallen 84%, according to an analysis by Lazard, a financial advisory firm that publishes annual estimates of the total cost of producing electricity.

Even five years ago, Ritchie said she was quite pessimistic because the costs for clean energy were so high. That doesn’t worry her anymore.

“We’ve seen this really dramatic change,” she said. “Solar and wind have gone from being the most expensive energy technologies by far to being cheaper than fossil fuels. That’s a fundamental shift and will change the speed at which we move toward low carbon technologies.”

The shift in cost is moving so quickly it’s hard even for experts to keep up.

“If you’re looking at data that even from just a few years ago you’re really behind,” said Ritchie.

These shifts aren’t just happening in the United States, but worldwide. While China is still the largest single global carbon emitter and is still building coal-fired power plants, it’s also moving extremely quickly into renewables.

New solar, wind and hydroelectric power in China accounted for 59% of the world’s new renewable in 2023, according to S&P Global.

“Last year alone, China deployed as much solar as the United States has in its entire history,” said Ritchie.

The International Energy Agency also says demand for oil, coal and gas will peak by 2030 as the number of electric vehicles on the road globally increases and China continues to move towards wind and solar.

That prediction is based on the current policies of the nations of the world.

That’s still too high to keep to the Paris Agreement goal of limiting the rise in average global temperatures.

But Hayhoe points out that when the first National Climate Assessment was issued in 2000, the estimate was that we could be heading to as much as a 7.2 to 9 degree increase by the end of the century. Today, the predictions are that 4.8 degree warmer world by the end of the century. "And that number goes down with every new step we take up the mountain," she said.

There’s hope on the horizon

Ritchie says the work necessary to fix climate change can seem overwhelming but it’s actually not as bad as it might seem. "The solutions overlap, so in tackling one problem you're making others better at the same time," she said.

Keeping this front and center can be hard. The same voices that have been denying climate change for decades now have added what’s known as doomerism to their toolbox – saying it’s too late and there’s no hope.

Even those who are overwhelmed by climate change can be frozen into inaction, said Hayhoe.

“We have people who are so panicked that they descend into this very unhelpful doomerism,” she said.

Meanwhile, Gore is also among those in awe of the progress humanity has made.

“If you had said years ago (that) in the year 2023 80% of all the new electricity generation installed worldwide is going to be solar and wind, I would have said ‘Wow. That's great!’ But that's what happened last year. If somebody had said 20% of all new vehicles sold worldwide would be electric vehicles, wow that's incredible as well,” he told USA TODAY in March.

“I often cite the famous saying from the late economist Rudy Dornbusch who said things take longer ‘than you think they will, but then they happen faster than you thought they could,'” he said.

Contributing: Michael Collins, USA TODAY