The Tipping Points of Climate Change: How Will Our World Change? Earth.Org Martina Igini Jan 11th 2024Prior to the Industrial Revolution and all the subsequent detrimental human activities, the global average amount of carbon dioxide was about 280 parts per million (ppm). Today, that level is close to 420 ppm; and every tonne of CO2 emissions adds to global warming. The IPCC has identified several so-called ‘tipping points of climate change’, critical thresholds in a system that, if exceeded, can lead to irreversible consequences. But when exactly will we reach them, who will bear the brunt, and, most importantly, is there a way to avoid it?
What Are the Tipping Points of Climate Change? .......The Intergovernmental Panel on Climate Change (IPCC) defines tipping 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.”he last time carbon dioxide levels on our planet were as high as today was more than 4 million years ago. And it did not take us long to get to where we are now. Within just 60 years or so, the annual rate of increase in atmospheric CO2 was about 100 times faster than previous natural increases. Prior to the Industrial Revolution and all the subsequent detrimental human activities, the global average amount of carbon dioxide was about 280 parts per million (ppm). Today, that level is close to 420 ppm. Every tonne of CO2 emissions adds to global warming. This tight correlation is highly suggestive of the fact that increasing anthropogenic greenhouse gas emissions is going to cause drastic changes in weather patterns, habitation, and biodiversity. The truth is that, in response to global warming, many of the world’s ecosystems are already getting closer and closer to catastrophic and potentially irreversible alterations. Climate science is clear about one thing: the only way we can stop further warming is by achieving net zero greenhouse gas emissions. However, given the thermal inertia of the earth’s system, further warming over the next decade is still unavoidable, even if we were to reach net-zero emissions tomorrow. With this in mind, there is no sugar-coating of the fact that humanity is going to inevitably be confronted with increasingly frequent and severe hazards such as droughts and rising sea levels in the years to come.
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 Permafrost Ocean circulation and temperature (AMOC) Monsoons Amazon Rainforests Antarctic ice sheets Coral reef die-offs.
When Will We Reach The Tipping Points of Climate Change? In the early 2000s, there was a general consensus among scientists that most tipping points could be reached in the event of a 4C-increase in global temperatures. However, more recent assessments found that exceeding 1.5C of global warming risks crossing several of these thresholds. That is why climate scientists across the globe have long called governments for more serious commitments to keep the global temperature rise below 1.5C. The IPCC describes this as a “vital” necessity if we want to avoid the devastating impact of extreme weather events in the coming decades and, even worse, pass the burden on to future generations. The Earth’s surface temperature has already increased by nearly 1.2C compared with the average in 1850–1900 and we are perfectly on track to reach the much feared 1.5C threshold between 2026 and 2042 in a scenario where emissions are not rapidly reduced.
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; and 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. The melting of Greenland’s massive ice sheet is already occurring so rapidly that it is now the main factor in global sea level rise, according to satellite data from 2022. In the past two decades, Greenland lost more than 5,100 billion tons (4,700 billion metric tons) of ice, an amount that is enough to flood the entire United States in half a metre (1.5 feet) of water.
2. Permafrost.......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.
3. Atlantic Meridional Overturning Circulation (AMOC)........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.......read on and none of it is good news. https://earth.org/tipping-points-of-climate-change/