A decade ago this week, the world saw a major triumph in climate diplomacy as the Paris Agreement was signed at the COP21 UN climate talks in the French capital.

After the disappointing outcome of COP15 in Copenhagen in 2009, the fact that 159 nations made legally binding promises to reduce their greenhouse gas emissions seemed like a historic win for the planet.

What ultimately got the agreement signed was a bottom-up approach designed around nationally determined contributions (NDCs) – each country’s efforts to reduce their own emissions and adapt to the climate crisis.

In the year leading up to the summit, the COP21 presidency had consulted privately with national climate representatives to discuss issues they found problematic and work towards consensus.

Unlike in Copenhagen, negotiators felt that their concerns were being taken into account and were more willing to embrace the task of pushing for emissions reductions in their home nations.

The United States and China, the world’s two largest emitters, both committed to the agreement – a crucial step that helped galvanized global climate action.

So, 10 years on, where has the Paris Agreement left us? Here are six important developments – both negative and positive – we’ve seen over the last decade.

Temperatures have kept rising, but not as quickly

The Paris Agreement aims to limit average global temperature rise to 1.5 degrees Celsius above pre-industrial levels – a level we may have already reached.

And based on projections released at COP30 last month, global heating is on track to reach between 2.3 and 2.6 degrees by the year 2100, assuming countries achieve all of their current NDCs.

“It’s clear that we were able to make an impact,” says Joseph Giguere, a climate data science research technician at Climate Central and one of the authors of its recent Ten Years of the Paris Agreement report.

“We have seen a decrease in our projected warming, but it’s also clear that we’re nowhere near close enough to the initial Paris Agreement goals.”

According to Climate Action Tracker, the world would have been on track for 3.6 degrees of heating this century if the Paris Agreement hadn’t been signed.

“So it’s not been nothing, but it’s not nearly enough if we want to avoid dangerous heat in the future,” Giguere continues.

According to Global Carbon Budget, greenhouse gas emissions are still rising, but also more slowly – at a rate of 0.3 percent per year, compared to 1.9 percent per year between 2005 and 2015.

Many countries haven’t lived up to their promises

Numerous countries have been either unwilling or unable to set appropriate targets to reduce emissions and then implement them.

It’s worth noting that while countries are legally required to submit NDCs under the Paris Agreement, they are not required to actually meet them.

In a recent article in Nature Climate Change, Paula Castro, a professor for energy and environment at the University of Zurich’s Center for Energy and the Environment, identifies various reasons why such gaps persist.

Global South countries, for example, lack the financial and technological resources needed to take effective climate action.

“Many governments – especially those in developing countries – still lack the capacity to design and implement policies and establish effective monitoring, reporting and verification systems,” she writes.

Changes in government and insufficient support from the public, she adds, “can deeply affect climate policy in a very short time.”

Keith Stewart, a senior strategist at Greenpeace Canada and sessional instructor at the University of Toronto, believes civil society can play a critical role in pressuring political leaders to act.

“The Paris Agreement can help everyone level up, but it’s never going to be top down,” he says. “We’ve got to do the hard work at home to build support for those alternatives.”

Renewable energy has taken off

The use of renewable energy sources, such as wind, tidal and particularly solar, has risen exponentially in the past decade.

“Ten years ago, the key problem was: how do we get renewable power online when it’s more expensive than fossil fuels?” Stewart recalls.

“Now, renewables are cheaper than fossil fuels.”

As a result, the world’s electricity capacity from renewables has increased by 140 percent, or 2,600 gigawatts, over the past nine years, according to a United Nations Climate Action report.

In comparison, electricity capacity from fossil fuels has grown by just 16 percent during this period.

Speaking at an event in Brasília, Brazil, in February, UN Climate Change Executive Secretary Simon Stiell compared the growing divide between investments in renewable energy and fossil fuels.

In 2024, the world invested about USD 2 trillion in renewable energy and infrastructure, he said.

“That’s twice as much as was invested in fossil fuels last year. Investors know that clean energy makes far more sense.”

Climate denial has continued

Despite the overwhelming evidence that the climate crisis is caused by humans, there’s still intense political pushback against that scientific consensus.

“One of the reasons I think the pushback is so fierce right now is because fossil fuel companies know they’re facing an existential threat,” says Stewart.

“They know that they used to be able to rely on the invisible hand of the market to keep them in business. Now, they need the very visible iron fist of the state.”

The days of China and the U.S. agreeing on the need to cut fossil fuel use are long gone, too.

While China has invested heavily in renewables, the U.S. has exited the Paris Agreement twice under President Donald Trump, who considers the climate crisis a hoax.

Other countries have also elected governments ideologically opposed to a green transition and anything that might dent the profits of oil and gas companies.

And yet, the low cost and ubiquity of renewables has made them highly appealing to countries in Europe and across the Global South looking to wean themselves off imported petroleum.

“They are going full speed ahead on the energy transition because it’s good for climate, which they recognize – but also, no one can block their access to the wind and the sun,” Stewart points out.

Misinformation has reached new levels

Even as surveys show that a majority of people around the world want climate action, there is still growing misinformation, especially on social media, regarding the effects and science of global heating – much of it now driven by AI.

“I have been working on climate change since the mid-90s, and I’ve seen every iteration of climate denial and misinformation out there,” says Stewart.

“The challenge now is that it’s so much more sophisticated and pervasive than it used to be. It used to be that you were fighting against full page ads in the New York Times. Now there’s AI slop coming to us from every which way.”

The oil and gas lobby has picked up lessons from the tobacco industry, he says, “including some of the same PR companies and scientists, where their motto is ‘doubt is our product – we want to cast doubt on the science, on the severity of the problem, and there isn’t anything that can be done.’”

The effects of the climate crisis are already being felt

In 2024, the world exceeded 1.5 degrees of global heating for an entire calendar year for the first time.

That doesn’t mean the 1.5-degree target set in the Paris Agreement has been breached, as that threshold refers to a long-term average spanning decades.

However, it does mean we’re getting close: scientists have estimated that we’re currently at approximately 1.3 degrees, and the effects are already being felt.

According to a study by the Grantham Institute, the climate crisis caused an estimated 16,600 excess deaths across 854 European cities this summer. The true number is likely to be much higher as these cities represent only around 30 percent of Europe’s population.

The Climate Central report also lists some of the impacts of the climate crisis across the globe.

In 2023, for example, the Amazon basin experienced its hottest dry season on record, causing drought and the death of hundreds of freshwater species – which would have been virtually impossible without human-caused climate change.

“Today, the region is warming about 1.4 times faster than the global average,” it says. “Since the Paris Agreement signing in 2015, the likelihood of such events has increased tenfold.”

Similarly, heatwaves like the one that caused Australia’s devastating bushfires in 2019–20 “are now about 2.5 times more likely and 0.9°C hotter than they would have been without human interference.”

Pre-monsoon heatwaves in India and Pakistan, meanwhile, are now 30 times more likely and 2.1 degrees hotter.

And regions around the world – from Southern Europe to Africa to the Indian subcontinent and Africa – are dealing with more frequent droughts, crop failures, heat-related deaths and power demand spikes.

The past 10 years have been a mixed bag: while the climate crisis has accelerated, it would have been far worse without the Paris Agreement.

One thing is clear: if we want to keep our planet livable for future generations, we’ll need to step up our climate action in the decades to come.