Think summer is hot now? Here’s how hot it would be without nature.

According to research from scientists working with Conservation International (CI) published in Proceedings of the National Academy of Sciences (PNAS), it is Earth’s biosphere to thank for not yet reaching this critical threshold.

The paper, co-authored by Conservation International scientists Johan Rockström, Director of the Potsdam Institute for Climate Impact Research and chief scientist at CI; CI scientists Dave Hole, Bronson Griscom, Mike Mascia; and partners, details the often downplayed or hidden ‘climate stabilization’ role played by the biosphere.

Currently, oceans, forests and other ecosystems absorb and store half of humanity’s annual carbon footprint in what the authors call “a vast subsidy to the world economy.” To effectively avert further, and far more dangerous impacts from climate change, focus must be on both preserving and enhancing nature’s climate stabilization role right alongside efforts to transition away from fossil fuels.

Yet the biosphere has already been profoundly altered by humanity, which has destroyed half of the world’s plant biomass. If current trends continue, some regions in the tropics could become a net source of carbon, rather than a sink.

Globally, less than 25% of all land area remains mostly unaffected by human impacts, with just 5% of the oceans untouched. Ultimately, this puts nature’s own ability to mitigate climate change significantly at risk.

“Troublingly, the biosphere’s natural balance is slowly succumbing to human pressures and climate change impacts,” said Rockström. “Humanity needs to act now – as stewards of nature – to restore and protect the vast ecosystems that halve our carbon emissions each year. Otherwise, we will not meet the critical benchmarks for the coming decade, as outlined in the Paris Agreement.”

In the short term, this stewardship must include three core elements, according to the researchers:

1. Halving emissions each decade to achieve carbon neutrality by 2050,
2. Shifting forestry and farming methods away from a reliance on habitat degradation and destruction and
3. Restoring and expanding natural carbon-absorbing ecosystems  

The researchers found that large scale stewardship of the biosphere could reduce warming by 0.3 degreee Celsius by the end of this century – a vital contribution to “remaining well below 2 degree Celsius,” the goal of the Paris Climate Agreement. To achieve such stewardship over the next decade, CI scientists urge collaboration between the public and private sectors, collectively establishing emissions targets and working with Indigenous peoples locally to protect nature.

To avoid potentially irreversible biosphere damage and worsening climate change, these efforts must begin urgently, globally and in parallel, scaling exponentially over the coming decade. This study sounds a clarion call on the level of ambition needed and the urgency of action – there is just a small window of time remaining to take decisive action on biosphere stewardship.