Our Overflowing Bathtub: COP30 and a Decade After Paris

By Ellie Johnston
December 16, 2025

When your bathtub is overflowing with water, what is the first thing you should do? Even a young child knows the answer. Simply, turn the water off.

Scientists have long pointed out that the amount of greenhouse gases in our atmosphere is quickly overflowing, and we need to turn the emissions off. The consequences are disastrous and already rippling across our world in the form of impacts like rapidly intensifying hurricanes, coral reef die offs, extreme wildfire conditions, and disruptions to age-old seasonal weather patterns. And if we don’t turn off the emissions, it’s expected to get much worse.

To assess the recent COP30 climate talks in Belém, Brazil and where we sit a decade after passing the Paris Climate Agreement, we have to face the troubling reality that the bathtub is overflowing faster than ever. One of the biggest announcements that arrived during COP30 was that CO₂ emissions continued to grow in 2025. With emissions growing, it is as if there is still a hand on the bathtub tap turning the volume of water up while the tub is overflowing.

At COP30, countries failed to reach consensus on explicitly naming the biggest source of emissions—fossil fuels—and didn’t come up with a way to ensure that the individual national pledges to reduce emissions add up to sufficient emission reductions globally. While some are finding other indicators of progress in Belém, we must stay cleareyed that all the conversations at the climate negotiations are undermined by the fact that our emissions problem is still getting worse.

If we don’t get global emissions under control, the need for adaptation finance quickly rises. At COP26 in Glasgow, developed countries agreed to mobilize $40 billion per year in funding for developing countries to respond to climate impacts by 2025, however, insufficient progress was made in Belém to ensure that even this relatively small amount of funding is assured. It is estimated that $310 billion per year by 2035 is needed for developing countries to adapt. We can start grabbing mops and towels to clean up the overflowing mess from the tub, but it’s going to be ineffective if the tap isn’t turned off.

So where do we go from here? Fortunately, we know what to do. We know where the emissions come from and we have a variety of technologies that are increasingly cheaper to use than the old emissions-producing technology. While overall progress is still insufficient, there are signs of change—for example, in the first half of this year there was more electricity produced from renewable energy than coal according to the energy analytics group Ember. On top of this momentum, we also saw an encouraging amount of dialogue from governments about phasing out fossil fuels, and follow-up conversations are already being planned for 2026.

We are in a tough place but, as I highlighted during COP30, much can still be done. The simulation tools we have developed at Climate Interactive with MIT Sloan provide an easy-to-use synthesis of the best available science, factoring in the latest energy and emissions data, so that anyone can see for themselves what it takes—try it out.