The year was 2015. ‘Uptown Funk’ with Bruno Mars was at the top of the music charts. Jurassic World was the most popular new movie in theaters. And decades of futility in international climate negotiations was about to come to an end in Paris.

After years of inaction despite constant warnings from climate scientists, hopes had been high for a breakthrough in climate agreements in 2009, leading up to the U.N. summit — known as COP15 — in Copenhagen.

But just a few weeks before that event began, a hacker broke into a server at the University of East Anglia’s Climatic Research Unit and released a tranche of climate scientists’ stolen emails. Though there was no indication of wrongdoing in those emails, some phrases taken out of context, combined with the then-unusual nature of the public release of private email correspondence derailed the Copenhagen summit, which was ultimately widely considered a failure.

Climate science denial and policy obstruction thrived in the ensuing years. That was exemplified by an incident in which then-Sen. James Inhofe, a Republican from Oklahoma, brought a snowball to the floor of the Senate in February 2015, because he apparently believed that winter snow proved that global warming was a hoax. (It doesn’t.) Global climate pollution had continued its seemingly inexorable rise, with fossil fuels accounting for two-thirds of global electricity generation compared to less than 5% from wind and solar energy in that year.

A graph showing how pollution emissions have skyrocketed since the mid 20th century.
Annual global greenhouse gas emissions. Created by Dana Nuccitelli with data from Our World In Data, based on Jones et al. (2023).

According to the International Energy Agency, based on government policies in place in 2015, global greenhouse gas emissions were on track to cause a potentially catastrophic 3.5 degrees Celsius (6.3 degrees Fahrenheit) of global warming by 2100.

As BuzzFeed News put it, in a world that is even just 3 degrees Celsius warmer, “deadly heat waves, massive wildfires, and damaging downpours will come far more often and hit much harder than they do today. The ocean will be hotter too and more acidic, causing fish declines and likely the end of coral reefs. In fact, a quarter or so of the Earth’s species may go extinct in such conditions or be headed that way. Our coastlines would be reshaped, a consequence of sea levels rising foot after foot, century after century, drowning places like Charleston, South Carolina’s Market Street, downtown Providence, Rhode Island, and the Space Center in Houston.”

And in December 2015, there was little evidence to suggest that this existential disaster would be averted.

But then at the COP21 Paris international climate negotiations, a breakthrough changed the course of humanity.

Progress on global warming since 2015

In the Paris agreement, 196 countries pledged to hold “the increase in the global average temperature to well below 2°C above preindustrial levels” and pursue efforts “to limit the temperature increase to 1.5°C.” Meeting those targets would require every country to implement climate policies to significantly curb their emissions of heat-trapping greenhouse gases. And though most countries are not yet on track to meet their Paris commitments, they have nevertheless implemented policies to make progress toward those targets, like the Inflation Reduction Act in the U.S. As a result of that progress, global emissions are on a substantially better track today than they were in 2015.

How quickly is renewable energy growing?

That’s largely due to the rapid deployment of wind and solar energy, and more recently, electric vehicles. Thanks to policies in countries like Germany to encourage the early adoption of clean energy technologies, the costs of wind and solar energy and batteries have fallen dramatically over the past decade. As a result, solar and wind energy are the cheapest sources of new electricity in most cases today, and electric vehicles are beginning to have lower total monthly costs than equivalent gasoline-fueled cars.

Those low clean technology costs combined with policy incentives in many countries have resulted in a rapid and exponentially rising rate of deployment, especially over the past three years. For example, solar panels today cost just 6% as much as they did in 2007 and less than half as much as in 2015.

Solar and wind energy accounted for less than 5% of global electricity production eight years ago; today their share is up to 14% and projected to reach 30% in 2030.

A bar graph showing that renewable energy is expected to make a larger share of global electricity generation by 2030.
Global electricity generation by source and year. Created by Dana Nuccitelli with data from the International Energy Agency and Our World in Data.

Solar installations are growing so fast that more solar panels were installed in the past three years than were deployed in the entire history of human civilization through 2020. And that number is on track to nearly double in the next three years.

A stacked bar chart showing that the capacity of solar energy added in the last three years is the same as all the years in human history before that combined.
Global solar power generation capacity added in different time frames. Created by Dana Nuccitelli with data from Bloomberg New Energy Finance.

How fast are EV sales growing?

Electric vehicle sales are growing even faster. In 2017, fully electric and plug-in hybrid vehicles accounted for just 1% of all new American car sales. Today their share is up to nearly 10%, including more than one in four new car sales in California. Globally, electric vehicles were expected to account for about 18% of new car sales in 2023, including nearly 40% in China and well over 20% in Europe. Norway is the global leader, with electric models accounting for over 90% of its new car sales.

And the popularity of EVs has grown so fast that of all the electric vehicles ever built by humans, three-quarters have been sold in the past three years alone.

A stacked bar chart showing that three times more electric vehicles were sold in 2023, 2022, and 2021 than in all the years before in. human history combined.
Global electric vehicle sales during different time frames. Created by Dana Nuccitelli with data from EV Volumes and Statista.

As a result of new climate policies and this clean technology growth, the International Energy Agency now projects that global climate pollution in 2030 will be about 7.5 billion tons (or nearly 20%) lower than in the pre-Paris agreement pathway. Based on current climate policies around the world, various groups estimate that we’re now on track for around 2.5°C (4.5°F) global warming by 2100.

On the one hand, that’s not yet good enough to meet the target set in the Paris agreement. On the other hand, climate policies and clean technologies deployed over just the past eight years have already erased a full degree Celsius of global warming from the future world in 2100. Governments need to do more in the coming years to bring the Paris goals within reach, but the progress made over just the past eight years has been remarkable, especially in comparison to the prior decades of futility.

Dana Nuccitelli, research coordinator for the nonprofit Citizens' Climate Lobby, is an environmental scientist, writer, and author of 'Climatology versus Pseudoscience,' published in 2015. He has published...