A major report highlights that the planet has reached its first critical climate tipping point. This means that warm water coral reefs are now facing a long-term decline. This is a serious concern for hundreds of millions of people who depend on these reefs.
The report, compiled by 160 scientists from 23 countries, states that the world is also close to reaching other dangerous tipping points. These include the Amazon rainforest drying out, major ocean currents collapsing, and ice sheets melting away.
Tipping points are moments when a large natural system reaches a stage where severe damage is unavoidable. Coral reefs are vital for ocean life, supporting about a quarter of all marine species. They are also very sensitive to rising global temperatures.
The scientists warn that unless global temperatures are reduced to 1.2C (and eventually to at least 1C) as quickly as possible, warm water coral reefs will not survive in any significant way. Global heating has already reached about 1.4C above pre-industrial levels.
The report estimates that coral reefs reached a tipping point when global temperatures rose between 1C and 1.5C. This threshold could be crossed within the next 10 years if greenhouse gas emissions are not cut rapidly.
Professor Tim Lenton from the University of Exeter, a lead author of the report, stated that the widespread dieback of warm water coral reefs is already happening. He explained that this is already affecting people globally.
The report points to areas like the Caribbean, where reefs are struggling due to heatwaves, low biodiversity, and disease outbreaks. These factors are pushing the reefs towards collapse.
However, some experts have a slightly different view. Professor Peter Mumby from the University of Queensland acknowledges that coral reefs are declining. But he also noted that there is new evidence suggesting some corals might adapt and survive even if global temperatures rise to 2C.
Professor Mumby stressed the need for strong action on climate change and better local management of reefs. He is concerned that the report might lead some people to believe that coral reefs are doomed, which he feels is not the case. He worries that if people think reefs cannot be saved, they might stop trying to protect them.
Dr. Mike Barrett from WWF-UK, a co-author of the report, emphasised that protecting reefs is more important than ever. He said the situation requires an urgent response.
He mentioned that some coral reefs, known as ‘refugia’, are less affected by climate impacts. Protecting these areas is crucial to provide seeds for future recovery if the climate can be stabilised.
Dr. Tracy Ainsworth, from the International Coral Reef Society, added that reef ecosystems are changing in many places. They may no longer be dominated by corals or are losing their diversity.
“The future of coral reefs is one of transformation, ecosystem restructure and new challenges,” she said. “Our challenge now is to understand how all of these different ecosystems are reorganising and how we can ensure they continue to support diverse marine life and communities.”
The Australian Institute of Marine Science noted that global figures can mask important regional differences. They also pointed out that global temperatures have not yet stabilised, meaning there is still a small chance to act.
Professor Lenton also warned that parts of the West Antarctic and Greenland ice sheets are dangerously close to their tipping point. The melting of land-based ice contributes to rising sea levels.
He predicted that global warming is likely to exceed 1.5C around 2030, which will increase the risk of further damaging tipping points.
The Amazon rainforest is also closer to its tipping point than previously thought, due to climate change and deforestation.
The report does offer some hope. It suggests that positive tipping points, such as the rapid adoption of electric vehicles, could also have a powerful effect, helping to reduce greenhouse gas emissions quickly. The race is on to bring these positive changes forward to avoid the severe consequences of further tipping points in the Earth’s systems.