The earth's average temperature is constantly rising, even though it has been partly slow over the years. Right now, many people are worried that the temperature will rise further to extreme temperatures that cause difficult conditions here on earth. Unfortunately, this can become a reality.
Normally, the temperature rises a few degrees in a hundred years, but now it goes faster. SMHI - Sveriges meteorologiska och hydrologiska institut (The Swedish institute for meterology and hydrology) describe how the average temperature on earth will increase between 2-6 degrees celcius (35-42 degrees fahrenheit) at the end of the century depending on the climate scenario used.
The risk when 2 degrees become a fact, is that the earth takes over the temperature rise we are seeing globally according to the scientist Johan Rockström. Natural disasters like huge floods and hurricanes become the earthly response to a higher temperature, and natural systems thereafter starts moving without us humans being able to control them.
What will happen is that someday we will reach four degrees (a crucial degree when large parts of the earth's ecosystem are knocked out) and what can we expect then?
A major risk at four degrees celcius (39 degrees fahrenheit) is that very large amounts of methane gas are released, which previously laid under the ice sheets (permafrost) and under our seabed.
A four-degree celcius increase (39 degrees fahrenheit) is enough to create a rampant climate development on the whole earth in the form of temperature increases. With a four degree celcius (39 degrees fahrenheit) rise in temperature, the majority of all the earth's countries, 80%, will turn into deserts. There will be such extreme heat waves that all what was previously green turns into sand.
The good news for today's earthlings is that at least a four-degree temperature (39 degrees fahrenheit) rise will take place in 50 years at the earliest. That's a time when humanity should already should have chosen to live in space (on the moon).
See under the heading Survival to see different possibilities for survival under future climatic conditions.
Source: Naturskyddsföreningens rapport "Den globala uppvärmningens konsekvenser" ,"SMHI:s rapport "Klimatet förändras och det påverkar dig." och ETC:s artikel "Världen om fyra grader." 2019-03-19.
Se en förklarande film från SMHI (2020) om jordens framtida klimat.