In 2015, nearly 200 countries adopted the Paris Agreement, the first global pact to fight climate change. It was a commitment to keep global warming "well below" 2 C compared to pre-industrial times, while striving to limit it to 1.5 C.
Ten years later, those same countries will meet in Belem, Brazil, from Nov. 10 to 21 for this year's annual United Nations climate summit, COP30.
Over the past decade, both atmospheric levels of greenhouse gases that cause climate change and global temperatures have continued rising to record-breaking levels.
So what has changed for climate change since the Paris Agreement was signed?
Here's a comparison of the world then and today, in terms of: the actual climate, clean technologies, countries' polices and laws, and where the world is putting its money.
How our current and future climate has changed
In December 2015, when the Paris Agreement was signed, the average global temperature over five years was 0.97 C higher than it was in pre-industrial times. In December 2024, it was 1.35 C higher, meaning the Earth has warmed more than 0.3 C in the past decade.
According to the 2025 UN Emissions Gap Report, released this morning, the world is currently on track for 2.3 C of warming by 2100 if countries can and do implement all their climate commitments.
How will that feel?
On a global scale, it means the number of potentially deadly hot days per year will double, says a new report from World Weather Attribution and Climate Central.
Friederike Otto, co-author of the report, said a 1.3 C temperature difference since pre-industrial times feels "negligible" when you step outside, but doubling that with more global warming "means the difference between life and death [for] thousands of people, and of course, also ecosystems."
On the other hand, when the Paris Agreement was signed, the world was on track for 4 C of warming by 2100. That would have brought triple the number of hot days we see today.
"We don't have a four-degree baseline anymore, arguably thanks to the Paris Agreement. That is hugely important," Otto said. But we're still "very far away from where the Paris Agreement, and thus all the ratifying countries, [say] we want to be."
From EVs to renewable power, how everyday technologies have changed
Global temperatures aren't the only things that have evolved since 2015. When the Paris Agreement was signed, many people had never even seen an electric vehicle, noted Clea Schumer, research associate at the World Resources Institute.
"Now there seems to be one on every street corner," she added at a recent news conference about a report she co-authored that looks at how the world is doing on the changes it needs to make to reach the Paris targets. EV sales have been the only measure "on track" recently, although they fell below target this year, despite predictions that one in four new cars sold worldwide would be electric in 2025.
In the past 10 years, there has also been huge growth in renewable power generation. A recent report from the global energy think-tank Ember showed that during the first half of 2025, for the first time ever, renewables were a bigger source of electricity globally than coal, making up 34.3 per cent of the electricity mix, compared to 33.1 per cent for coal.
Schumer said clean energy has grown by an average of 13 per cent per year since 2020. But it needs to grow at double that rate. "The world is adding clean power," she said. "Just not fast enough."
How our laws and regulations have changed
A new report from the Deep Decarbonization Initiative analyzed how the Paris Agreement affected climate action and found it had "real impact," said Harvey Waisman, the initiative's director, at a news conference. "National policies have been implemented and have accelerated the spread of a number of low-carbon technologies and solutions."
Chris Bataille, who worked on a profile of Canada accompanying the main report, said the Paris Agreement provided the "backing for a global shift."
In Canada, the agreement allowed the federal government to introduce national policies on carbon pricing, zero emissions vehicles and a net zero goal (although consumer carbon pricing has been scrapped and the vehicle policy paused). It also prompted provincial and municipal governments to introduce their own policies, such as bans on new gas connections in buildings.
Bataille said Europe implemented strong policies related to carbon pricing, and China ramped up development of technologies such as solar, batteries and EVs. It began exporting "enormous amounts" of solar to developing countries such as Pakistan and South Africa.
Jessica Green, a professor of political science at the University of Toronto, thinks a big success of the Paris Agreement is that it requires all countries to take climate action. "That's really important, particularly for middle-income and emerging economies who were ... more or less off the hook in previous versions."
That said, she's skeptical the Paris Agreement had much to do with the growth of clean energy, which she credits to low prices due to decades of investment from China.
How we've changed where our money is going
The UN says investment in green energy surpassed $2 trillion US in 2024, drawing $800 billion more than fossil fuels last year.
Green thinks one of the biggest impacts of the Paris Agreement is another kind of investment -- requiring developed countries to help developing countries both fight climate change and adapt to it.
The goal was to provide $100 billion US annually, in the form of things like loans, grants or credits. Individual countries could contribute through institutions such as the Canada International Development Agency and also pool resources with multiple countries through institutions such as the World Bank.
In a report released last week, the UN finds that climate finance for adaptation fell from $28 billion in 2022 to $25 billion in 2023, despite a commitment to provide $50 billion per year by 2025.
However, the total amount of climate finance invested has been growing since 2015. The OECD reported that it finally hit the $100-billion annual goal in 2022, and said this week that the goal was likely to have been met in 2023 as well.
What does all this say about the Paris Agreement?
"It's working, but we need to work at it harder," Bataille said, echoing many recent reports.
Green, on the other hand, says the agreement has "failed by its own metric," given how far we are from its temperature goals.
In her new book, Existential Politics: Why Global Climate Institutions Are Failing and How to Fix Them, Green suggests trade treaties may be a more effective way to slow climate change. She thinks focusing on the energy transition -- shutting down fossil fuels and building up renewables -- instead of emissions would get us closer to our goals.
Bataille also suggests adapting global trade rules, and making some climate actions mandatory instead of voluntary as they have been so far.
He added that the annual UN climate meetings might be better spent focusing on how to make climate progress in individual economic sectors. If it did so, he said, "I think it could work very well going into the future."