written 18 July 2021
published 25 July 2021
Scripps Institution of Oceanography, an organization not given to hysteria, reported in 2017 that "business as usual" presented a 1:20 chance of raising Earth's temperature 5°C above preindustrial levels within thirty years, with odds increasing to 1:4 twenty years later. This article examines descriptions of a hotter Earth.
From Green Facts: as Earth warms to 4°C
Oceanic Impact: Increasing atmospheric carbon dioxide concentration not only warms the oceans but increases the acidity of the water. The combination of thermally induced bleaching events, ocean acidification, and sea-level rise threatens coral reefs, which provide coastal flood protection, as well as nursery grounds and habitat for many fish species. Coral reefs are already starting to bleach and dissolve.
Temperatures: The largest warming will occur over land. Summer months will be warmer than the most extreme heatwaves presently experienced. Increases of more than 6°C (11°F) in average monthly summer temperatures would be expected in the Mediterranean, North Africa, the Middle East, tropical South America, central Africa, and all tropical islands in the Pacific, which would regularly experience heat waves of lethal magnitude and duration.
Water Issues: With increasing heat, drought is projected to increase, exacerbating existing water scarcity in northern and eastern Africa, the Middle East, South Asia, southern Europe, large parts of North America and South America, and southern Australia. While wetter conditions are projected for northern North America, northern Europe, and Siberia, and some monsoon regions, such as the Ganges and Nile.
Biodiversity: Large-scale loss of biodiversity is likely as rapid warming drives Earth´s ecosystems into a state unknown in human experience, with more frequent extreme weather events, such as forest loss due to droughts and wildfire, exacerbated by changes in land use and agricultural expansion, likely leading to increased mortality and species extinction, dramatically reducing ecosystem services on which society depends.
Food Availability: New research suggests a rising risk of crop yield reductions as the world rapidly warms. Large negative effects have been observed at high and extreme temperatures in several regions including India, Africa, the United States, and Australia, with reduction in both yields and nutrition.
From Big Think: commentary on a map showing a 4°C warmer world.
The following areas are uninhabitable due to floods, drought or extreme weather: the Eastern Seaboard of the U.S., all of Mexico and Central America, the middle third of South America, Mozambique, Madagascar, Pakistan, Indochina, and most of Indonesia. The last inhabitants of the Southwest U.S. are migrating north. The Colorado river is a mere trickle. Deglaciation means Peru is dry and uninhabitable. Bangladesh is largely abandoned, as is South India.
Most of the U.S., the rest of South America, almost all of Africa and the southern halves of Europe and Asia, become barren deserts.
Some land, where populations are currently concentrated, is lost to 2 meters of sea level rise. In the U.S. for instance, counties directly on the shoreline constitute less than 10% of the total land area but account for 40% of the total population.
From Job One for Humanity:
There are three degrees and definitions for climate destabilization.
Catastrophic Climate Destabilization: associated with a measurement of carbon above 400ppm. We are currently at 420ppm, and already in the beginning stages of catastrophic climate destabilization. Last year, global warming-caused storms, floods, seasonal disruption, wildfires, and droughts cost the US almost $450 billion.
Irreversible Climate Destabilization: associated with a measurement of carbon above 425 ppm. Earth will have moved away from the relatively stable temperatures experienced during the previous hundreds of thousands of years. Earth will most likely not recover for hundreds or even thousands of years, costing the nations of the world hundreds of trillions of dollars.
Extinction-Level Climate Destabilization: associated with atmospheric carbon greater than 600 ppm. The temperature range associated with extinction-level climate destabilization is 5°C and above, producing the eventual extinction of more than half of the species on earth and most, if not all, of humanity.
Take a moment. Look around at this wonderful world. We risk losing it all. A half century of self-serving corporate disinformation and Republican intransigence means there are no graceful solutions left. To avoid disaster, we must reduce carbon emissions by 50% in the next 100 months! But this requires a degree of social cohesion sadly lacking these days. Are we really too selfish to survive?