TIPPING POINT ALARM

I take no pleasure in being a purveyor of doom and gloom, but we really, really, need to start taking very serious notice of the environmental threats our planet, and therefore we, are facing. Few politicians seem to be listening and many are stone deaf to the alarm calls. As a scientist, I try to look at evidence on which to base my views but rare is the politician who listens to scientists unless it suits their political purpose.

Let’s consider some of the current situations on the verge of tipping life on Earth into catastrophe. Here is a (scary) refined list of the most serious environmental tipping points facing us and our world. I have given the source of scientific backing for each[1]:

 1. Greenland Ice Sheet collapse

• What is it? Massive melting of the Greenland ice sheet.
• Tipping point: ~1.5 °C of global warming may trigger self-reinforcing melt due to ice–albedo feedback (dark water absorbs more heat than reflective ice).
• Impact: Adds ~7m to global sea levels over centuries; regional weather disruption.
• Source: Nature (2019), IPCC AR6. https://www.ipcc.ch/assessment-report/ar6/

 2. West Antarctic Ice Sheet (WAIS) collapse

• What is it? Loss of ice grounded below sea level.
• Tipping point: already showing signs of Marine Ice Sheet Instability, especially Thwaites Glacier (the “Doomsday Glacier”).
• Impact: Potential 3–5m sea level rise.
• Source: PNAS (2020), ESA Climate Office. https://doi.org/10.1073/pnas.1910114117

 3. Atlantic Meridional Overturning Circulation (AMOC) slowdown/shutdown

• What is it? Disruption of a key Atlantic ocean current (includes Gulf Stream).
• Tipping point: Possibly within this century; recent studies suggest collapse risk between 2025–2100.
• Impact: Massive shifts in rainfall (African/Asian monsoons), European cooling, US East Coast flooding.
• Source: Nature Climate Change (2021), IPCC AR6. https://www.ipcc.ch/report/ar6/wg1/

 4. Amazon Rainforest dieback

• What is it? Conversion of rainforest to savanna.
• Tipping point: Combination of deforestation (17% lost already) + warming/droughts.
• Impact: Collapse of global carbon sink, loss of rainfall for agriculture across South America.
• Source: Lenton et al. (2019). https://pubmed.ncbi.nlm.nih.gov/31776487/

 5. Arctic Permafrost thaw

• What is it? Melting of frozen soils releases CO₂ & methane (25x more potent than CO₂).
• Tipping point: Some regions already thawing abruptly.
• Impact: Amplifies warming, undermines Paris targets.
• Source: Nature Communications (2020), IPCC AR6.

https://www.nature.com/articles/s41467-023-41105-z

[1] I have use AI to generate and check much of this blog item.CJB