There are literally hundreds of "points of no return" or tipping points in climate change:
They are the temperature increases beyond which these changes become inevitable:
The Amazon Rainforest will turn into a savanna
The western United States will desertify
The ice at the north pole will completely melt in summers
The Greenland ice sheet will completely melt
The West Antarctic ice sheet will completely melt
The East Antarctic ice sheet will completely melt
The various corals will die (depending on their locations and the species of coral)
The ocean will become acidified to the point that shellfish can no longer make shells
Various major cities around the world will be flooded (depending on their locations)
Various species will become extinct (depending on their vulnerabilities)
The Gulf Stream will largely shut down
The glaciers will melt (depending on their location)
Permafrost will melt and release CO2 and methane (depending on its location)
Ocean clathrates will melt and release methane (depending on their depth and location)
And so on....
Scientists believe that most of these tipping points will happen at various degrees of warming above 2C, which is why the goal has long been to keep warming below that point. But tipping points would likely happen at all sorts of different temperatures at different times, and many may happen across a range of temperatures. Plus even when certain changes have become inevitable, many will take decades and even hundreds of years. So even the experts can only estimate when they occur.
However, from what I have read, we have already passed at least certain tipping points (unless we actively remove CO2 from the atmosphere and sequester it again). For instance, the sealevel will inevitably rise much higher over many years, and Miami and New Orleans inevitably will be flooded. Also, the permafrost in certain areas is already melting.
The single biggest unknown variable of climate change is how people will act in the coming years. And people are notoriously unpredictable.
They are the temperature increases beyond which these changes become inevitable:
The Amazon Rainforest will turn into a savanna
The western United States will desertify
The ice at the north pole will completely melt in summers
The Greenland ice sheet will completely melt
The West Antarctic ice sheet will completely melt
The East Antarctic ice sheet will completely melt
The various corals will die (depending on their locations and the species of coral)
The ocean will become acidified to the point that shellfish can no longer make shells
Various major cities around the world will be flooded (depending on their locations)
Various species will become extinct (depending on their vulnerabilities)
The Gulf Stream will largely shut down
The glaciers will melt (depending on their location)
Permafrost will melt and release CO2 and methane (depending on its location)
Ocean clathrates will melt and release methane (depending on their depth and location)
And so on....
Scientists believe that most of these tipping points will happen at various degrees of warming above 2C, which is why the goal has long been to keep warming below that point. But tipping points would likely happen at all sorts of different temperatures at different times, and many may happen across a range of temperatures. Plus even when certain changes have become inevitable, many will take decades and even hundreds of years. So even the experts can only estimate when they occur.
However, from what I have read, we have already passed at least certain tipping points (unless we actively remove CO2 from the atmosphere and sequester it again). For instance, the sealevel will inevitably rise much higher over many years, and Miami and New Orleans inevitably will be flooded. Also, the permafrost in certain areas is already melting.
The single biggest unknown variable of climate change is how people will act in the coming years. And people are notoriously unpredictable.
