IMPACTS of climate change / global warming are now becoming evident, and impacts will become far worse in the future if substantial mitigating action is not taken soon.  For the earth as a whole, impacts will be overwhelmingly negative. Regionally, there will be variations. While nothing will ever be 100% certain, expert opinion is warning us that a variety of disasters awaits. Here is a list of the worst effects:

Water: Glaciers and snow packs that now provide water to many millions of people are melting, forshadowing severe regional water shortages in the future.

Food: Disruption of food supplies and agriculture will occur for many millions. Increased rain in the winter and increased evaporation in the summer will stress crops. While slight amounts of warming can increase crops in some localities, more warming produces negative effects on crops, which will lead to severe regional food shortages. The earth already has 800 million people that go to bed hungry each night. Global warming will increase this number.

Migration: Food and water shortages, coupled with sea level rise in costal regions, will lead to migration of many millions of displaced and desperate people.

Wars: Tensions between nations stressed by water and food shortages, along with migrations, will lead to more wars. There are some indications that these factors were the underlying cause of the tragic Darfur conflict. Political instability will increase. Terrorism due to desperate groups will likely increase.

Economics and Finance System Breakdown: Recent events have exhibited the fragility of the worldwide financial and economic systems. The severe environmental and political strains due to global warming impacts, coupled with the mass psychological effects of fear, may well severely effect financial and economic stability worldwide. This includes Europe and the United States.

Disease: As warming occurs, disease vectors including insects move north, affecting people, crops, and forests in many regions.

Droughts: As warming occurs, more evaporation occurs, causing more regional droughts.

Fires: As warming occurs, more precipitation causes more underbrush to grow, which dries during the summer, providing tinder for wildfires. Cf. the recent increase in California fires.

Hurricanes: Although there are competing factors, there is evidence that global warming may well be increasing the strength of hurricanes.

Sea Level Rise: Recent evidence shows that glaciers in Antarctica are disintegrating at a faster rate than before, due to complex ice dynamics. If these glaciers disintegrate, sea level rise will be measured in meters, not centimeters, and will affect hundreds of millions of people. Coastal regions in many parts of the world will be flooded. Time scales for such effects, previously thought to be hundreds of years, are being substantially revised to much shorter times. The 2007 IPCC Science Report mentions these effects, but the sea level rise numbers in this report do NOT include these potentially very large effects.

Failed States: This is increasingly being mentioned as a distinct possibility for some underdeveloped countries stressed by global warming effects without sufficient resources to adapt.

OTHER: There are many more potential impacts of global warming. For a detailed discussion, please see the 2007 Impacts, Adaptation, and Vulnerability IPCC Report (Vol II).