World could cross a dire climate threshold in 2028, says new report

A new scientific report warns that the world could deplete its remaining carbon allowance in just three years, driven by historic levels of greenhouse gas pollution.

If global emissions remain at their current pace, the threshold for 1.5 degrees Celsius (2.6 degrees Fahrenheit) of warming—seen as a critical benchmark—could soon be surpassed, said the report, cited by Live Science.

In 2020, the UN’s Intergovernmental Panel on Climate Change (IPCC) projected the remaining carbon allowance was around 500bn tonnes. Since then, emissions have continued to surge, and with the next IPCC assessment not expected until 2029, the researchers aimed to fill the information gap with this updated analysis.

Breaching the 1.5 C limit increases the chances of irreversible climate disruption, such as intensifying heatwaves, prolonged droughts, and destabilisation of major ice sheets in Greenland and Antarctica.

Nearly 200 nations committed to keeping temperature rise “well below” 2 degrees Celsius—and ideally to 1.5 degrees—under the 2015 Paris Agreement.

The recent analysis by more than 60 leading scientists shows how rapidly that goal is slipping away. As of now, only 130bn tonnes of allowable carbon dioxide remain before the 1.5 C target is likely out of reach. Meanwhile, humans are pumping out more than 42bn tonnes each year. The findings were published June 19 in Earth System Science Data.

Co-author Dr Aimée Slangen, research leader at the NIOZ Royal Netherlands Institute for Sea Research, said in a statement: “Since 1900, the global mean sea level has risen by around 228mm. This seemingly small number is having an outsized impact on low-lying coastal areas, making storm surges more damaging and causing more coastal erosion, posing a threat to humans and coastal ecosystems.”

She continued: “The concerning part is that we know that sea-level rise in response to climate change is relatively slow, which means that we have already locked in further increases in the coming years and decades.” 

Joeri Rogelj, professor of climate science and policy at Imperial College London, also a co-author of the study, added: “The window to stay within 1.5 C is rapidly closing. Global warming is already affecting the lives of billions of people around the world. Every small increase in warming matters, leading to more frequent, more intense weather extremes.”

The scientists’ study evaluates ten key climate indicators, including global emissions trends, temperature anomalies, ocean heat storage, rising seas, and other markers of planetary stress.

The report paints a troubling picture: Earth is heating up at a rate of roughly 0.27 C (0.49 degrees Fahrenheit) per decade, and global surface temperatures are now approximately 1.24 C (2.2 F) above preindustrial norms.

Today, Earth is absorbing heat at more than twice the rate observed in the late 20th century. In the current decade alone, that rate has climbed by 25% compared with the 2010s. Most of this surplus heat—around 90%—is entering the oceans, where it is causing cascading effects, including sea level rise, ice melt, and ecosystem disruptions.

The implications of continued heating are far-reaching. One analysis predicts that harvests of crops like wheat and corn in countries such as the US, China, and Russia could fall by as much as 40% by the century’s end. Meanwhile, another study found that roughly 30% of global land was affected by moderate to severe drought in 2022, hinting at upcoming worsening water scarcity.

Despite these dire projections, the authors note a possible turning point may be near. Emissions may reach their highest levels before the end of this decade and then start to decline—provided there’s rapid adoption of clean technologies and substantial reductions in carbon pollution.

“Emissions over the next decade will determine how soon and how fast 1.5°C of warming is reached,” said Rogelj. “They need to be swiftly reduced to meet the climate goals of the Paris Agreement.”