The paleoclimate records show that past climate changes have included both steady, linear changes as well as abrupt, non-linear changes, where small increases in global warming produced large and irreversible impacts once tipping points were passed. Climate scientists now warn that anthropogenic emissions are pushing the planet’s climate system toward such tipping points sooner than previously expected, and that impacts could be catastrophic.
Among potential impacts of passing climate tipping points are the disappearance of Arctic summer sea ice, disintegration of the Greenland Ice Sheet, collapse of the West Antarctic Ice Sheet, disappearance of the Hindu-Kush-Himalayan-Tibetan glaciers that supply water to all of Asia’s major rivers, shutdown of the Atlantic Thermohaline Circulation, and dieback of Amazonian and boreal forests. The catastrophic impacts from these events would include many meters of sea level rise, water shortages, megadroughts, and famine, and could lead to political instability and resource wars. Other impacts include release of methane and other global warming gases from permafrost and ocean hydrates, which could set off runaway feedbacks.
With the tipping points fast-approaching, there must be a focus on near-term mitigation measures which include: reducing emissions of black carbon, methane, and tropospheric ozone; reducing production and consumption of HFCs under the Montreal Protocol; and expanding biochar production, among others.
Contact Xiaopu Sun at IGSD for more information