As more than 66,000 world leaders, negotiators, delegates, and observers meet this week in Baku, Azerbaijan at the COP29 climate summit in what’s shaping up to be the hottest year on record, they’re facing a one-two-punch of grim news: greenhouse gas emissions are still climbing, and one of the world’s largest carbon dioxide polluters — yes, the US — is likely to back out of the process altogether.

And after Donald Trump’s win in the 2024 United States presidential election, the US — the world’s second-largest greenhouse gas emitter — is poised to extract more fossil fuels, pull back clean technology incentives, and may once again withdraw the country from the Paris agreement.

To meet international climate targets under the Paris climate agreement, global greenhouse gas emissions need to be falling fast. Yet humanity’s output is on track to reach another record high this year, up 0.8 percent from last year, according to a new report this week from Global Carbon Budget, a research unit at the University of Exeter in the United Kingdom. This trajectory means that the goal of capping the rise of global average temperatures below 2.7 degrees Fahrenheit (1.5 degrees Celsius) is almost completely out of reach.

The conference, where countries hammer out the details of how they will do their share to address climate change, is already off to a rocky start, struggling just to adopt an agenda. France and Argentina have also withdrawn their top negotiators.

“We’ve just had the hottest day, the hottest months, the hottest years, and the hottest decade in the history books,” UN Secretary-General António Guterres told the conference. “Climate disasters are piling up — harming those who’ve done the least, the most.”

So at a time when the world needs to be doing more than ever to limit warming, transition to clean energy, and adapt to the unavoidable shifts underway, momentum is slowing.

Yet it hasn’t stopped. Though emissions are rising, their rate of increase is slowing down, and a decline may be on the horizon. Wind and solar power are still surging and electric vehicles are gaining market share. Even with diminished political will, the trends are moving in the right direction for the climate. But progress is fragile and far too slow.

What’s driving up global emissions right now?

Last year, Climate Analytics, a think tank, anticipated that there was a 70 percent chance that global emissions would begin to decline this year. The new Carbon Budget findings show that the world is more likely to be in the 30 percent scenario. “I think their analysis is generally really robust and sound,” said Neil Grant, a researcher at Climate Analytics. “There is still some chance that emissions might fall this year, but it certainly looks very unlikely.”

Digging into the top-line greenhouse gas emissions number reveals a complicated story behind why emissions are up.

The big reason is that fossil fuel consumption is up. Oil and gas account for the bulk of this increase in emissions, with coal a distant third. While greenhouse gasses in the atmosphere are rising, their output is level or falling from some of the largest historical emitters. The European Union’s emissions are declining. US emissions are holding steady. China, the world’s largest greenhouse gas emitter, is on track to see its output grow by just 0.2 percent this year, one of the tiniest increases in years.

Bucking this trend are many developing countries like India, currently the world’s third-largest emitter. India has seen a huge increase in renewable energy deployment, but its still developing energy from all sources, including fossil fuels. The Global Carbon Budget found India’s fossil fuel emissions are on track to increase 4.6 percent this year.

There are a few additional factors that drove up emissions this year. The lingering effects of El Niño helped push global temperatures to record highs. Extraordinary heat waves in India and China pushed up energy demand for cooling, and that meant burning more fossil fuels. “We’re beginning to see some of those negative feedback loops where the climate crisis itself is impacting on the energy system and making it harder to reduce emissions,” Grant said.

Still, there are glimmers of good news. More than 30 countries have already managed to grow their economies while cutting carbon dioxide pollution, a clear sign that coal, oil, and natural gas are not the only paths to prosperity. These countries have already summited their emissions peaks and are now on the descent, breaking a pattern that has held for nearly two centuries.

“Most countries in the world, even if they haven’t peaked yet, you see that the trajectory is approaching peak, and in countries where emissions are declining, usually they’re declining faster,” said Pierre Friedlingstein, a researcher at the University of Exeter who led the Global Carbon Budget report.

What’s bending the curve? Friedlingstein said it’s because countries are switching to cleaner energy sources. That means turning away from carbon-spewing coal toward natural gas, which emits about half of the greenhouse gasses per unit of energy, or using energy from the sun and the wind, which emits close to none. Electrifying vehicles so they don’t have to burn oil is another key factor. Increasing energy efficiency is also negating rising energy demand.

Government policies initially drove these trends, but now economics have started to take the wheel. Tactics to reduce greenhouse gas emissions often save money and energy sources like wind and solar power are often the cheapest way to put electrons on the power grid.

It’s important to note that burning fossil fuels isn’t the only way humanity is increasing carbon dioxide concentrations in the atmosphere; damaging and destroying landscapes that absorb carbon — forests, mangroves, wetlands, prairies — also lead to a net increase in greenhouse gasses. Carbon dioxide isn’t the only greenhouse gas of note either. Methane, which is about 30 times more potent when it comes to trapping heat, is also contributing to warming. It can leak from natural gas infrastructure and is also a byproduct of agriculture.

Conversely, restoring ecosystems that soak up emissions from the air can keep warming in check. Unchecked deforestation is slowing down in many parts of the world and in others, it’s beginning to reverse. “The long-term trend in forestation is going in the right direction,” Friedlingstein said. “This is what helps to balance the book with fossil fuel emissions.”

Where greenhouse gas emissions go is up to us now

While greenhouse gas emissions are now increasing at a tiny fraction of their pace throughout much of the industrial era, there’s no sign at the moment that they’ve reached a peak, nor a guarantee that they will decline.

Friedlingstein said we may be in an era where emissions plateau, still adding to the volume of heat trapping gasses in the atmosphere at the highest levels in history. And a plateau could stretch on for a long time. Environmental groups have raised the alarm that the ravenous power demand from data centers behind artificial intelligence and cryptocurrencies would spike emissions upward again, but much of that demand could still be met with renewable energy or nuclear power, and so far, they haven’t led to a carbon dioxide spike.

On the other hand, countries can take deliberate steps to bend emissions curves downward at a faster rate. Countries need to set ambitious climate goals for themselves, invest in cleaner energy alternatives, and hold themselves accountable. “In a sense, it’s a simple recipe,” Friedlingstein said.

In practice, it remains an extraordinary challenge.

Many countries are coping with inflation, making it harder to invest in big projects. Some are worried about securing their energy resources amid fears of international conflict, like how Russia’s invasion of Ukraine disrupted natural gas supplies in Europe. Many parts of the world experiencing the most acute damages from climate change are also those that contributed the least to the problem and have the fewest resources to adapt to it.

Clean energy needs to scale up further as well. So does energy efficiency. About 30 percent of global electricity came from low-emissions sources in 2023. “While renewables have grown fast, demand has grown faster,” said Grant. “And we know that the tipping point of peaking will come when renewables grow faster than energy demand growth.” He added that the distribution of clean energy technology so far has skewed mainly toward wealthy countries and not those facing the largest increases in energy demand, biggest spikes in air pollution, and worst impacts of climate change.

The United Nations’s Independent High Level Expert Group on Climate Finance estimated that poorer countries will need $1.3 trillion per year by 2035 to deal with global warming. This is once again shaping up to be one of the biggest sticking points at COP29 as negotiators suss out who is to pay how much and by when.

Though the world is likely to miss one of the most ambitious climate targets, the case for curbing greenhouse gas emissions remains strong. Every bit of averted warming — every degree or even fraction of a degree — reduces damages, saves money, and protects lives. The open question is how much we’ll do to change course.