The Berlin-based Climate Analytics research institute released a new report to coincide with the summit. Its calculations indicate that the global average temperature will inevitably exceed the Paris Agreement threshold of 1.5°C above pre-industrial levels.
Bill Hare, the institute’s chief executive, describes this as an “overshoot”. He said the breach was now physically unavoidable, but political decisions would determine how far temperatures rise and how long it takes to bring warming back below 1.5°C.
The 1.7°C pathway
According to the report, rapidly phasing out fossil energy and sharply reducing methane emissions could still limit peak warming to around 1.7°C. Temperatures could reach that level in the 2070s before the increase falls to 1.2–1.3°C by 2100.
Achieving this would require fossil fuel-related carbon dioxide emissions to fall to roughly half their current level by 2035. Fossil energy would need to be replaced in electricity generation, transport, buildings and industry. Energy efficiency would also have to improve so that demand itself declines.
Methane emissions would need to fall substantially in the energy, waste and agricultural sectors. The pathway also relies on ending deforestation, restoring natural ecosystems and expanding technologies that remove carbon dioxide from the atmosphere.
Marcia Rocha, the report’s coordinator, said nearly all the necessary tools and technologies were already available. In her view, clean alternatives tend to be affordable and safe, while also offering a pragmatic response to geopolitical uncertainty.
Every tenth of a degree matters
The difference between 1.5°C and 1.7°C may look small, but its consequences can be measured. Climate Analytics estimates that a third more people would be exposed to heatwaves at 1.7°C than at 1.5°C. If warming reached 1.8°C, the number affected could rise by another 10 per cent.
Each additional tenth of a degree increases the risks from extreme weather, rising sea levels and major tipping points in the Earth’s systems. If temperatures could be brought rapidly back from a 1.7°C peak to 1.5°C, the report says there would still be a chance of avoiding the loss of shallow-water coral reefs, the melting of the West Antarctic ice sheet, changes to Atlantic Ocean circulation and the decline of the Amazon rainforest.
Emissions are still rising
A recent global carbon budget cited by HVG suggests that fossil fuel emissions could fall by 0.4 per cent this year, after increasing by 1.2 per cent last year. Total carbon dioxide emissions caused by human activity, including those resulting from land use, could nevertheless continue to rise.
The preliminary estimate for this year is 43.8 billion tonnes. That would be 500 million tonnes, or 1.15 per cent, above last year’s figure of 43.3 billion tonnes.
If current trends continue unchanged, human-caused warming could reach 2.6°C by 2100. Even if today’s most ambitious emissions-reduction pledges are fulfilled, the increase is still projected to be around 2°C. Global warming had already reached 1.37°C last year.
Source: HVG
