Record greenhouse gas emissions could deplete Earth's 'carbon budget' in just three years.
According to a recent assessment, there are only 143 billion tons of carbon dioxide left before exceeding the Paris Agreement target. With annual emissions exceeding 46 billion tons, this threshold could be reached much sooner than expected. Researchers, whose work was published in
Earth System Science Data, emphasize the urgency of the situation.
Illustration image Pixabay
Current global warming, estimated at 1.24 degrees Celsius above pre-industrial averages, is accelerating. Oceans absorb about 90% of this excess heat, disrupting ecosystems and accelerating sea level rise. The consequences on coastal areas and populations are already visible.
Impacts on agriculture could be devastating, with potential yield reductions of 40% for key crops like corn and wheat. Meanwhile, drought is intensifying, already affecting 30% of land surfaces.
Despite this bleak picture, scientists note that emissions could peak this decade before declining. This transition depends on rapid adoption of renewable energy and drastic carbon emission reductions. The coming years will be crucial to limit the damage.
What is Earth's 'carbon budget'?
The 'carbon budget' represents the total amount of carbon dioxide humanity can still emit before exceeding a certain global warming threshold. This concept is important for understanding the limits not to cross to avoid the worst impacts of climate change.
It is calculated by considering past emissions and future projections, as well as Earth's capacity to absorb these emissions. Once this budget is exhausted, chances of limiting warming to 1.5 degrees Celsius become slim.
Scientists use climate models to estimate this budget, which decreases each year with continued emissions. The speed at which we deplete it largely depends on our collective actions to reduce emissions.
Why is 1.5 degrees Celsius a critical threshold?
The 1.5 degrees Celsius threshold has been identified as a tipping point beyond which climate change impacts become much more severe and irreversible. This figure isn't arbitrary but based on solid scientific grounds.
Beyond this threshold, risks of extreme weather events, biodiversity loss and sea level rise increase significantly. Ecosystems and human societies could reach points of no return, with major consequences.