2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Even if we stop all anthropogenic greenhouse gas emissions from 2020, the average air temperature on the planet will continue to rise due to the large amount of water vapor in the atmosphere, low albedo of the earth's surface and self-sustaining melting of permafrost. This may indicate that the Earth's climate system has already passed the point of no return. Scientists have come to this conclusion using the ESCIMO climate model, but in other models the results of their calculations have yet to be verified. The simulation results and conclusions of the authors are published in Scientific Reports.
For several decades, climatologists have been discussing the possibility that the Earth's climate system may pass the "climate tipping point": some of its parameters (average air temperature, water vapor content in the atmosphere and concentration of carbon dioxide in the air) will exceed the threshold, followed by irreversible climate change. Scientists recently clarified that the critical moment may even come earlier than previously thought.
Jorgen Randers and Ulrich Goluke of the Norwegian Business School BI have predicted mean air temperature changes up to 2500 years using the ESCIMO model. It includes blocks of ocean, atmosphere, forests (and other land biomes), biomass, and describes the interactions between them. Within the framework of this model, three indicators are considered as key for increasing temperature - self-sustaining melting of permafrost, albedo of the earth's surface (that is, its ability to reflect sunlight) and water vapor content in the atmosphere. Scientists used two scenarios: the first assumes a complete cessation of anthropogenic greenhouse gas emissions in 2100, and the second - already in 2020.
Sensitivity of the global average temperature to changes in parameter values in ESCIMO for scenarios 1 and 2.
It turned out that according to ESCIMO, the average air temperature on the planet will continue to rise up to 2500, even if all anthropogenic greenhouse gas emissions are immediately stopped in 2020. The authors of the study noted that in the first decades after the cessation of emissions, the concentration of carbon dioxide in the air can return to pre-industrial levels due to its absorption by the soil, ocean and biomass. However, this will not stop warming due to the key parameters of the model: apparently, their values passed the point of no return even before 2020. Scientists have pointed to low current values of the albedo of the earth's surface and their further decline in the future. For example, between 2070 and 2300 in the ESCIMO model, the average ocean albedo will decrease from 0.080 to 0.067, and the albedo of the land surface - from 0.17 to 0.17. A similar situation will be observed with water vapor - its warming effect will remain strong by maintaining a sufficiently high air temperature.
Scientists noted that their report is based on only one climate model, moreover, not the most accurate and sophisticated, and called on other climatologists to verify their results using and combining other global models.
The results of the climate change predictions made by the authors of the report may be controversial, but the key indicators for the ESCIMO model really reach record values: for example, the carbon dioxide content in the atmosphere has become the highest in 23 million years, and the sea ice in the Arctic will completely disappear for the summer seasons. by 2050 (in 2020, the Arctic was already practically devoid of such ice from June to October).
