1000 years from now
Above 35°C wet bulb, life is impossible
Looking ahead, 1000 years is about as far as scientists or science fiction writers can imagine. Their worst-case scenario for climate change is dystopian:
Scorching skies over uninhabitable deserts ring the equator, the temperate zone becomes tropical, the arctic temperate, but without soils to grow crops. Sea levels are 30 meters higher than present and temperatures on average 7°C warmer. Coral reefs are long gone, and the sea regenerating into an ecological balance based on sponges and algae. (more)
Measures based on Intergovernmental Panel on Climate Change (IPCC) projections
For millennia to come
Ruins of cities abandoned either to rising water or intense heat will still be apparent on the landscape. Entire populations move as refugees to safer locales, which are themselves under pressure from smaller harvests and limited water supplies. War seems inevitable. Disasters are routine, either caused by social upset or natural forces that are exacerbated by climate change: droughts, floods, fires, and hurricanes. The pattern is familiar, leaving large parts of the Earth difficult to inhabit or impossible. High-density cities have to defend inhabitants in an unpredictable world.
Many animals and plants are already extinct from loss of habitat. Hemmed in by agriculture, they had nowhere to go. Forests and forest species suffer also with little margin to adapt. The most successful are generalists, hardy creatures that thrive in disturbed habitat, such as raccoons, mice, coyotes and deer. Species that live with humans are also successful, including food animals, parasites, pets, and detritivores such as rats and cockroaches. Warm, acidic, anoxic, and polluted oceans support few fish. Any fragment of Earth conceivably untouched is distant history.
Rising carbon dioxide levels from burning oil and gas trigger other natural sources that continue to release greenhouse gasses. Thawing permafrost expels methane in pulses. Peat bogs flooded with sea water disintegrate, releasing more carbon dioxide. Warmer oceans can also give off methane from shallow sea beds, and algae blooms leave shallow waters anoxic, sometimes shedding toxic microbes. Ocean currents, which have absorbed heat from the air can reverse and release that heat back to the winds.
After 1000 years the plastics currently in use have finally decomposed into soil, while carbon dioxide in the atmosphere and oceans remains for many thousands of years more. Natural processes that remove it: the weathering of rocks, building of soil and peat, and accumulating carbonate in shallow ocean deposits, are difficult to rush.
Can we find another way to live on Earth?
After the wars, the droughts, the floods, and the great losses that climate change will have wrought, other scenarios are also imaginable. Perhaps a global society will learn, as some native peoples learned in the past, how to maintain their ecosystem. Perhaps they will thrive. In such a future, perhaps, a much smaller population of people will be able to live well and educate their children to understand their role within the natural world. In such a vision, perhaps most of the land and sea will be wild but managed to foster bio-diversity and ecological health. A circular economy powered by renewable energy will produce no waste, recycling everything into new production. Labor will be automated and informed by cumulative expertise, allowing more attention to the details of production and recycling. Permaculture food forests might be intensely managed through robotics and even integrated into the city to recycle nutrients, produce local food, and offer beautiful spaces for people to learn about their local habitats. In different ecological regions local cultures might develop patterns of living, eating, crafts production, art, science, and literature specific to their place, which enrich their ecosystems rather than degrade them.
A thousand years from now the world will be damaged irrevocably, and less rich than it is now or has been in the past. People will still be here and will still be able to choose how to live.
Text: "The impacts of climate change at 1.5°C, 2°C and beyond." Climate Brief: Clear on Climate, 2019, from https://interactive.carbonbrief.org/impacts-climate-change-one-point-five-degrees-two-degrees/.
Wallace-Wells, D. (2018). "UN Says Climate Genocide is Coming. It’s Actually Worse Than That." New York Magazine (October 10, 2018).
"The best case for worst case scenarios." RealClimate: Climate science from climate scientists, 2019, from http://www.realclimate.org/index.php/archives/2019/02/the-best-case-for-worst-case-scenarios/comment-page-2/.
Image: Composite from Adobe Stock Images
CO2 & Temperature: United States Environmental Protection Agency. (2017). "Future of Climate Change." Retrieved 20 September 2018, from https://19january2017snapshot.epa.gov/climate-change-science/future-climate-change_.html.
Temperature: The Royal Society (2017). Climate Updates: What we have learned since IPCC 5th Assessment, The Royal Society, p.7. Retrieved 20 September 2018 from https://royalsociety.org/~/media/policy/Publications/2017/27-11-2017-Climate-change-updates-report.pdf
Sea Level: Horton, B. P., S. Rahmstorf, S. E. Engelhart and A. C. Kemp (2014). "Expert assessment of sea-level rise by AD 2100 and AD 2300." Quaternary Science Reviews 84: 1-6. https://www.sciencedirect.com/science/article/abs/pii/S0277379113004381
Population: No projections