In this lesson, we looked at the potential impacts of projected climate change on civilization and our environment. The key impacts under continuing anthropogenic carbon emissions are:
- Projected sea level rise could threaten many coastal and low-lying regions of the world by the end of this century; low-lying island nations could be submerged. Within two centuries, major east coast and Gulf coast cities would be severely impacted. Costs from damage to coastal infrastructure could rise to a third of a billion dollars for the U.S., and millions of individuals could be displaced.
- Certain species such as the Golden Toad have already gone extinct, at least in part due to climate change. Many other amphibians, and iconic megafauna such as the Polar Bear, are already under threat from climate changes. Projected losses of species could approach 1/3 with only 2°C additional warming, and well over half of all species with 3°C warming. The combined impact of warming oceans and increasing ocean acidity from anthropogenic greenhouse emissions, combined with other human-caused threats such as pollution and ozone depletion, place coral reefs—which account for 25% of the ocean's biodiversity—under threat of disappearance in as soon as a few decades.
- Shifting water resources threaten damage to societal infrastructure through increased precipitation intensity and flooding during certain seasons in some regions, and increased drought during other seasons in other regions. In regions such as the desert southwest of the U.S., decreasing water supply is on a collision course with increasing populations in cities such as Las Vegas and Phoenix.
- Health impacts of climate change are likely to include increased mortality due to more frequent and intense heat waves, increased spread of disease from more widespread flooding and drought, threats to health and life from more increased storm damage, and the poleward spread of tropical disease with warming temperatures.
- National security impacts of climate change include increased conflict arising from the competition between nations and groups for diminishing land, food, and water resources, and the need for additional national defense as new shipping routes and coastlines open as a result of diminished arctic sea ice.
Reminder - Complete all of the lesson tasks!
You have finished Lesson 9. Double-check the list of requirements on the first page of this lesson to make sure you have completed all of the activities listed there before beginning the next lesson.