The last 50 years of human activity have pushed us away from the environmental stability of the past 12,000 years.
Runaway global warming
As global temperature continues to rise, the unforeseen possibilities of catastrophic runaway global warming increases. Its scientific consensus that climate change is a non-linear phenomenon where tipping points play a crucial role. When warming rises above a certain threshold, self-reinforcing feedback loops set in, and the concentration of greenhouse gases increases rapidly. (eg. melting ice sheets not only absorb less of the sun’s heat and energy, but also release more harmful methane)
Discussions of climate change typically focus on low- to mid-range scenarios, with temperature increase of 1°C to 3°C. These would have severe consequences, with potentially devastating effects on the environment and human societies.
Non-negligible and less often considered ‘tail-end’ risk that temperatures might rise even further, causing unprecedented loss of landmass and ecosystems. In mid-range scenarios, entire ecosystems would collapse, much agricultural land would be lost, as would most reliable freshwater sources, leading to large-scale suffering and instability. In high-end scenarios, the scale of destruction is beyond our capacity to model, with a high likelihood of human civilization coming to an end
These estimates give a 10% chance of warming over 6 degrees, and perhaps a 1% chance of warming of 9 degrees. That would render large fractions of the Earth functionally uninhabitable, requiring at least a massive reorganisation of society. It would also probably increase conflict, and make us more vulnerable to other risks.
One possible solution. Manipulate the atmosphere, with the potential to reduce climate risk:
- carbon removal, directly remove carbon dioxide from the atmosphere (scale, price)
- solar geoengineering, reflecting light and heat from the sun back into space, particularly through the injection of aerosols or other particles into the stratosphere. today only computer models, should be more rigorously tested now.