Tipping Points
What are tipping points, and why should we care?
A climate “tipping point” refers to a threshold beyond which small changes to global temperatures can have big, irreversible effects.
For example, you’ve probably heard that scientists are concerned about the melting of the huge ice sheet that covers Greenland. If the world isn’t able to rein in global warming, the melting will eventually become self-sustaining and irreversible, researchers have determined.
That’s a tipping point.
If this threshold is crossed, the melting could raise sea levels by as much as 23 feet over the course of several centuries, swamping coastal cities around the world.
The idea of climate tipping points has been around for decades, although there is debate about how many there are and at what temperatures they will be reached. The big ones, however, are generally accepted to include the melting of the ice sheets in Antarctica and Greenland; the thawing of Arctic permafrost; the collapse of a major ocean circulation system; and the shrinking of the Amazon rainforest.
Recent research suggests that some of these changes may start to occur once global warming reaches between 1.5 and 2 degrees Celsius (2.7 and 3.6 degrees Fahrenheit) above preindustrial average temperatures. And the world is already 1.2 degrees Celsius warmer than it was in the 19th century.
Climate Tipping Points: The Thresholds that Could Reshape Our Planet
What is a Climate Tipping Point?
Understanding climate dynamics is complex, just like the interwoven systems that constitute our planet's biosphere. Think of our Earth as a finely balanced scale, and at the heart of these complexities lies the concept of the 'climate tipping point'.
A climate tipping point refers to a critical threshold in the earth's system, — a point of no return — where a small change can trigger a large, often irreversible, shift in the state of the environment. These shifts have the potential to cause havoc to ecosystems, wreak economic chaos, and pose an existential threat to humanity.
Why Should We Care?
The major concern with reaching a climate tipping point is that the scale and pace of change would outstrip our capacity to adapt. This may lead to decreased food production, displacement of people, and extinctions of species at a catastrophic rate. Moreover, these major shifts could stimulate additional environmental changes with potentially devastating ramifications.
The Stakes as We Cross Climate Tipping Points
Climate scientists find a rise of 1.5 degrees Celsius above pre-industrial levels as the crucial threshold to avoid disastrous environmental effects. Here are the what-ifs that scientists expect as we reach and possibly breach each climate tipping point:
1.5 Degrees Celsius
Even with a rise of 1.5 degrees, small islands and coastal cities would face severe sea level rise. 70-90% of all coral reef would die off. There would be increased weather extremities such as heatwaves, rainfall, and droughts, negatively impacting crop yields, especially in sub-Saharan Africa, Southeast Asia, and Central and South America.
2.0 Degrees Celsius
At 2.0 degrees, the scenarios turn grimmer — almost all the coral reefs would face extinction. Global sea levels would perhaps rise by around 0.46 meters by 2100, leading to more widespread coastal flooding. Severe heatwaves would become a regular occurrence. There are indications that Arctic summers would become ice-free and Greenland's ice loss would be irreversible.
4.0 Degrees Celsius
A 4-degree rise is a nightmare scenario, including a possible collapse of the Atlantic Meridional Overturning Circulation, disrupting global weather patterns. There would be a drastic reduction of plants’ photosynthetic ability leading to decrease in oxygen levels. In high altitudes, melting glaciers would threaten water supplies for millions of people.
6.0 - 8.0 Degrees Celsius
At these tipping points, the consequences are catastrophic—massive species loss, vast areas of the planet becoming uninhabitable due to extreme heat or flooding, and permafrost melt releasing millions of tonnes of methane, a potent greenhouse gas, into the atmosphere.
The climate tipping points indicate dire outcomes that we should certainly care about. We are not hostages to this future, and these extremities can be averted if we act now. However, recognizing the urgency is the first step towards meaningful global cooperation and action on mitigating climate change.