A new report by more than 200 scientists has warned that the Earth is on the verge of crossing major climate tipping points that could trigger a climate catastrophe in the next 10 years. The report, published in the journal Science, assessed the latest evidence for nine tipping elements in the Earth’s system, such as ice sheets, coral reefs, and ocean currents, that could undergo abrupt and irreversible changes due to global warming.
Climate tipping points are thresholds in the Earth’s system that, once crossed, could lead to self-sustaining and potentially irreversible changes, even if greenhouse gas emissions are reduced or stopped. For example, the melting of ice sheets could raise sea levels and alter ocean circulation, which in turn could affect weather patterns and ecosystems around the world. The collapse of coral reefs could reduce biodiversity and marine productivity, affecting food security and livelihoods for millions of people.
The concept of climate tipping points was first introduced by the Intergovernmental Panel on Climate Change (IPCC) two decades ago, but since then, new research has shown that some of these thresholds may be closer than previously thought. The new report synthesised the results of more than 200 studies to estimate the warming levels at which each tipping element could be triggered, as well as the impacts and timescales of the changes.
Which tipping points are likely to be crossed?
The report found that at current levels of global warming, which stand at roughly 1.2°C above pre-industrial levels, the Earth is already at risk of triggering six dangerous climate tipping points. These are:
- Greenland Ice Sheet collapse
- West Antarctic Ice Sheet collapse
- Collapse of ocean circulation in the polar region of the North Atlantic
- Coral reef die-off in the low latitudes
- Sudden thawing of permafrost in the Northern regions
- Abrupt sea ice loss in the Barents Sea
The report also found that four of these six tipping points become more likely as global warming exceeds 1.5°C, the lower limit of the Paris Agreement’s goal of limiting warming to well below 2°C. These are:
- Greenland Ice Sheet collapse
- West Antarctic Ice Sheet collapse
- Coral reef die-off in the low latitudes
- Sudden thawing of permafrost in the Northern regions
The report warned that crossing these tipping points could have cascading effects on other parts of the Earth’s system, creating a domino effect of climate disruption. For instance, the loss of ice sheets could accelerate the melting of mountain glaciers and Arctic sea ice, which could further amplify warming by reducing the Earth’s reflectivity. The weakening of ocean circulation could alter the distribution of heat and nutrients in the oceans, affecting marine life and regional climates. The release of carbon and methane from permafrost could increase greenhouse gas concentrations in the atmosphere, enhancing the greenhouse effect.
How can we avoid crossing the tipping points?
The report emphasised that the best way to avoid crossing the tipping points is to reduce greenhouse gas emissions as quickly and as deeply as possible, in line with the Paris Agreement and the latest IPCC report. The report also suggested that some tipping points could be delayed or reversed by enhancing the resilience of the Earth’s system, such as restoring natural ecosystems, increasing carbon sequestration, and deploying geoengineering technologies. However, the report cautioned that these measures are uncertain and could have unintended consequences, so they should not be seen as substitutes for emission reductions.
The report concluded that the Earth is approaching a critical juncture in its history, where the fate of the planet and humanity depends on the actions taken in the next decade. The report urged policymakers, businesses, and civil society to heed the scientific warnings and act with urgency and ambition to avoid crossing the climate tipping points and avert a climate catastrophe.
References:
2 Earth is closing in on catastrophic climate ‘tipping points’, over 200 scientists warn
3 Catastrophic change looms as Earth nears climate ‘tipping points’, report says
4 Climate change: What are the climate tipping points?
5 Climate change: Six tipping points ‘likely’ to be crossed
6 Climate change: Six tipping points ‘likely’ to be crossed – BBC News
Category: Science
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