Climate Tipping Points
What are Climate Tipping Points?
- The Intergovernmental Panel on Climate Change (IPCC) define stipping points as “critical thresholds in a system that, when exceeded, can lead to a significant change in the state of the system, often with an understanding that the change is irreversible.”
The IPCC identifies several tipping points of climate change.
Here are the 7 most likely to be crossed this century due to human activity:
- Greenland ice sheet
- Ocean circulation and temperature (AMOC)
- Amazon Rainforests
- Antarctic ice sheets
- Coral reef die-offs
What Happens If We Reach the Most Pressing Tipping Points?
1. Greenland Ice Sheet:
- The Arctic ice sheet is warming 3 to 4 times faster than the rest of the world, adding almost 1mm to global sea levels every year.
- This can be explained by the fact that, as the sun-reflecting ice surface melts as a consequence of global warming, deeper layers of the ocean as well as land are exposes.
- Because both the blue ocean and land absorb the sun’s energy better and faster, this vicious cycle inevitably leads to an increase in temperatures across the region and thus further melting.
- As the world’s second-largest ice sheet, the Arctic holds enough water that, if melted completely, could raise sea levels by 7.2 metres (22 feet).
- A 1.5C increase in average temperatures could be the threshold at which the region’s ice sheet melting would become irreversible.
- Permafrost refers to a ground that remains frozen for at least two consecutive years and is essentially a mixture of rock, soil, sediment, ice, and organic material.
- Permafrost is isolated from the atmosphere by a boundary called an “active layer”, consisting of live plants in summer, with added snow in winter.
- The active layer transfers heat from or to the permafrost.
- This permanently frozen layer below the Earth’s surface which covers parts of Siberia, Alaska northern Canada, and the Tibetan plateau also holds the largest global carbon reserve from plants and animals that died and decomposed over thousands of years.
- Scientists estimate that it contains about 1,400 billion tons of carbon, nearly double the amount present in the atmosphere.
- As the climate warms and permafrost begins to thaw, carbon dioxide and methane are released into the atmosphere.
- The spread of these highly toxic gases, scientists warn, would add up to 0.3C to global warming and could lead to humanity reaching other tipping points of climate change much faster.
- AMOC – or Atlantic Meridional Overturning Circulation – is a large system of ocean currents driven by differences in the density of water, which determines their temperature.
- The AMOC acts as a conveyor belt, redistributing heat throughout the Earth’s climate system by bringing it from the tropics in the Southern Hemisphere all the way to Greenland and carrying cold water back south.
- The freshwater input from glaciers’ melting, however, significantly weakens these currents.
- While the flow has already been reduced by about 15% in the last five decades, a weakening of 24% to 39% is expected even before the tipping point is reached, something that could happen as early as in 2100.
- A study published in 2021 found that AMOC is already at its weakest in over 1,600 years.
- “A slowdown of the AMOC”, the IPCC explains, “could have consequences around the world: rainfall in the Sahel region could reduce, hampering crop production; the summer monsoon in Asia could weaken; regional SLR [sea level rise] could increase around the Atlantic, and there might be more winter storms in Europe.”
- Farmers across the tropics, from the Amazon region in South America to West Africa and even India, count on seasonal monsoon cycles to grow their crops.
- As global warming affects their strength, timing, and duration, farmers are forced to relocate their agricultural practices elsewhere.
- This mass climate change-induced migration would inevitably decrease productivity and threaten food security not only in these regions but pretty much across the whole world, disrupting the livelihoods of over a billion people.
5. Amazon Rainforest:
- Disrupting monsoons and rain patterns across South America would add to the burden already experienced by the Amazon Rainforest, also referred to as “the world’s lungs”, due to deforestation.
- As the largest tropical rainforest on the planet and home to about three million species of plants and animals, the Amazon produces about half of its own rainfall by recycling moisture through evaporation and transpiration as air moves around.
- However, as the effects of climate change intensify, drought events are limiting the forest’s ability to influence rain patterns.
- Over the last 10 years, the Amazon rainforest experienced three “once-in-a-hundred-year” droughts.
6. Antarctic Ice Sheets:
- The Antarctic ice sheet, scientists argue, is already destabilising and it is very close to its tipping point even without added warming.
- The UN’s World Meteorological Organisation (WMO) reported that temperatures on Antarctica have increased by almost 3C over the past 50 years, with glaciers experiencing an accelerated retreat.
- Because the Antarctic ice sheet contains 58 metres of sea level rise equivalent over several centuries, scientists are growing worried about its recent behaviour.
Syllabus: Prelims + Mains; GS III – Environment