Carbon dioxide (CO₂) emissions generated by fossil fuels and cement production in the world, mainly responsible for the global warming that is affecting humanity, will grow again in 2025. Specifically, by 1.1% compared to 2024, as predicted by the Global Carbon Budget report, the analysis in which 130 international experts participate and which this year celebrates its twentieth edition. The big news, for yet another year, is that emissions will increase to 38.1 gigatons. Since the signing of the Paris Agreement in 2015, the key goal of which is to reduce greenhouse gas emissions so that they virtually disappear by mid-century, CO₂ emissions have grown by 9.8%.
The data are undoubtedly negative because they lead to the worsening of this crisis. The window to ensure that the increase in average temperature remains within the safety margins established in the Paris Agreement itself is increasingly closing. The pact stipulated that the average increase on Earth should remain below 2 degrees Celsius above pre-industrial levels, and as far as possible below 1.5. About half of the CO₂ expelled by human activities accumulates in the atmosphere for centuries. If we continue at the same pace as 2025, in just four years the so-called carbon budget to keep the global average temperature below 1.5 degrees will be exhausted.
In fact, the world of science believes it is inevitable that this 1.5 barrier will be overcome in a stable manner in the next decade. The only option left to meet the Paris Agreement would be for this overshoot to be only temporary, which would require drastic reductions in other short-lived greenhouse gases in the air, such as methane, and the uncertain techniques for capturing and storing carbon dioxide from the atmosphere.
If the current pace continues, the carbon budget to reach the 2-degree target will be exhausted within 25 years, the report further highlights. Pep Canadell, one of the coordinators of the report and executive director of the Carbol Global Project, talks about a sort of cat and mouse game, in which the world population and its demand for energy grow from year to year and renewable energies, despite increasing exponentially, do not completely cover all energy needs and replace fossil fuels.
But there is also some hope. “Peak emissions are very close,” Canadell says. “There are only a few years left,” and it will be during this decade, although Canadell does not dare specify it in a year. The ceiling on global emissions will be reached by the “exponential growth of renewable energy”. But reaching the peak, the expert warns, will not be “enough”, because what must happen immediately afterwards is for them to quickly drop to zero.
According to UN calculations, the new plans that countries are presenting as part of the Paris Agreement will lead to a reduction in emissions of all greenhouse gases – not just CO₂ – by 12% by 2035. Even if these are good data, they are not enough to remain within the safety margin: according to the UN, these emissions will have to be 55% lower within 10 years to respect the 1.5 and 35% path for 2 degrees.
These reductions are, for now, only estimates of what can be achieved with the implementation of the Paris Agreement and the promises of the countries that are part of the treaty. But what has happened so far is that since it was signed, global carbon dioxide emissions have grown by the aforementioned 9.8%.
Yes, there is a slowdown in the growth rate. In the just previous decade, between 2005 and 2015, the increase was 18.8%, almost double the following one.
In both cases, both in growth rates and in the next emissions peak and in the fall forecasts for 2035, China is the key. It is the world’s leading emitter of CO₂ – accumulating 32% of it globally – but it is also the leading country in terms of installing renewable energy and developing electric cars within and outside its borders.
For 2025, the report predicts that China’s CO₂ will grow by 0.4%, but with a large margin of uncertainty (between -0.9% and 2%), as Canadell acknowledges. To know the definitive data we will have to wait until next year. In any case, for the second consecutive year there has been a clear slowdown in emissions. This is due, the authors explain, “to moderate growth in energy consumption combined with extraordinary growth in renewable energy production,” which has led to stagnation in the use of coal.
For India, which accounts for 8% of global emissions, an increase of 1.4% is expected, significantly lower than the pace recorded so far. In addition to the growth of renewable energy, weather conditions have meant that less energy is needed this year.
This is exactly the opposite of what happened in the EU (6% of global emissions), where cold and windless conditions in many parts of Europe led to an increase in natural gas use and a 0.4% increase in carbon dioxide. This possible increase breaks a sustained trend in emissions in the EU. Canadell, however, is not worried as he believes it is something temporary related to the weather.
What worries him above all is the situation in the United States, the second largest emitting country in the world with a share of 13%. The report shows a 1.9% increase in emissions for this year. And this growth, which breaks the trend of recent years, is linked to the increase in natural gas prices (because the United States exported much more due to the invasion of Ukraine). This led to increased use of coal, which was seeing continued decline due to its higher costs compared to natural gas. This is the most dangerous of fossil fuels when it comes to global warming.
As for the future of the United States, Canadell believes that Donald Trump’s policies against renewable energy and in favor of fossil fuels, the main sponsors of the Republican Party, will have an impact on the country’s emissions. They will fall, the expert predicts, but more slowly than expected under the previous administration.
35 countries are in the lead
Canadell highlights two other positive points of this year’s edition. On the one hand, the existence of a group of countries – 35 nations that currently accumulate 27% of all carbon dioxide emissions on the planet – that significantly reduced their gases as their economies grew in the period between 2015 and 2024. This shows the path that can be followed. These countries include most of the EU members, including Germany, France, Spain, the United Kingdom, the United States, Australia and South Korea. In the previous decade, 2005-2014, there were half that number, 18.
The other point that the expert highlights is the decrease in CO₂ emissions linked to deforestation and changes in land use, which will decrease again in 2015. According to preliminary calculations contained in the report, adding the gases expelled from the fossil sector and those linked to land use, this year’s emissions should amount to 42.1 gigatons, just under the 42.4 of 2024.
