Jack Marley, environment editor to the Conversation, recently summed up the (mostly) bad news for global climate. Global temperatures, he writes, have been 1.5°C hotter than the pre-industrial average for almost two years now. The reason, overwhelmingly, is that greenhouse gas emissions are at record highs – from the burning of both fossil fuels and forests.
Predictions
The WMO Global Annual to Decadal Climate Update (2025–2029) projects that global temperatures will continue to rise, to near record levels in the next five years. Climate risks and impacts on societies will increase. Global mean temperature between 2025 and 2029 is expected to between 1.2°C and 1.9°C higher than the average over the years 1850-1900. There is an 80% chance that at least one year between 2025 and 2029 will be warmer than the warmest year on record (currently 2024). And there is an 86% chance that at least one year will be more than 1.5°C above the pre-industrial level.
Moreover, there is a 70% chance that the five-year average warming 2025-2029 will be higher than 1.5oC. This is likely to drive ‘more harmful heatwaves, extreme rainfall events, intense droughts, melting of ice sheets, sea ice, and glaciers, heating of the ocean, and rising sea levels.’ These predictions are scary. And we approach them with increasing speed.
Record heat
Year on year, the rise in global temperature is getting bigger. Normally, there will be a La Niña after an El Niño. ‘This will lower the global temperature by a couple of tenths of a degree Celsius,’ says Richard P. Allan, a professor of climate science at the University of Reading. But this time, there has been very little of this effect.
Human caused warming of the ocean is even accelerating – the year on year rise in temperature is itself getting bigger. Even to such an extent that it dominates to an ever greater extent over El Niño and other natural oscillations in the climate. This year, even during La Niña – when equatorial eastern Pacific waters are cooler than normal – the rest of the world’s oceans have remained remarkably warm.
Temperatures keep rising
Consequently, January 2025 was the hottest on record – 1.7°C hotter than the average January before the mass burning of coal, oil and gas. Does the ocean still cool down global temperatures? There are reasons to doubt this. A research station that has been taking the temperature of the western English Channel for more than 120 years now reports ‘almost continuous marine heatwave conditions’; says oceanographer Tim Smyth of the Plymouth Marine Laboratory.
A record-hot Atlantic Ocean is bad news for people living in the Caribbean and the south-east of North America. For it is here that hurricanes come into existence. The US National Oceanographic and Atmospheric Administration (NOAA) predicts an ‘above average’ number of cyclonic storms; largely due to warmer seawater at the ocean surface. But even this is hard to predict, as we now arrive at a situation not lived through before. Normally, climate scientists have several decades in the past to characterize future events. Now, there is no stable situation anymore on which to base their predictions.
How hot will it get?
One recent prediction was that Earth will be 2.7oC hotter by 2100, compared to the pre-industrial baseline. That is: IF governments would meet their emissions goals. And even this prediction may already be out of date, given the unexpectedly hot first half of 2025. One conclusion seems certain: conditions will be radically more hostile than anything our ancestors have experienced.
The big question then is: why does the rate of global warming accelerate? Ecologists Thomas Newsome of the University of Sydney and William Ripple of Oregon State University have the following to say about this. ‘Each year, we track 35 of the Earth’s vital signs, from sea ice extent to forests. [In 2024], 25 are now at record levels, all trending in the wrong directions.’
Trends
It is true. Renewable energy sources like wind and solar have grown rapidly; but fossil fuel use remains 14 times greater. Moreover, the concentration of aerosols that are effective at reflecting the Sun’s energy back into space and cooling the Earth (soot is one example), is falling. And there are other environmental issues that now feed into climate change, the authors say. There is deforestation, that shrinks the amount of carbon stored on land. Rising temperatures and extreme weather dry out, and contribute to burning other carbon-rich habitats, like marshes and peatlands. Sea ice, that reflected much of the incoming radiation, is melting.
But still this doesn’t predict how much the planet will heat up. Everything we do today, and in coming years, will lower it. On this front Sven Teske of the University of Sydney says: ‘despite daily negative news, the decarbonisation train has left the station. In 2024, renewables accounted for more than 90% of growth in electricity production globally. Electric vehicles became cost competitive, while heat pumps are developing fast and solar is on a winning streak. Renewables, energy efficiency and other measures have shifted the dial. The worst case scenario of expanded coal use, soaring emissions and a much hotter world is vanishingly unlikely.’ In other words: there is still hope!
Interesting? Then also read:
A dangerous new phase in climate change?
Towards less global warming
The future of renewable energy