What are some of the effects of global warming or climate change?

More intense heat waves lead to more heat-related deaths. Asthma and eczema in children have been linked to global warming. Intensity of storms and the flooding of major rivers are increasing. A study by the National Academy of Science in 2004 predicted a doubling of heat waves. More intense storms also cause increasing run-off that may pollute water supplies. California depends on the Sierra Nevada snow pack for water. Global warming could cut the snow pack by 29 percent in the next 100 years. Droughts may increase. When sea levels rise, coastal areas may disappear. Global warming has also contributed to forest fires in California. In the developing world, global warming is having a devastating effect; drought has destroyed crops. In Alaska in 2011, permafrost is thawing, causing mudslides on a road used by sightseers. Glaciers are receding. The average temperature in Alaska is rising three times faster than the average in the lower 48 states. The risk of floods is increasing. Erosion is threatening some parks. In the summers of 2009 and 2010, floods closed the road to one of a park's popular attractions. What used to be ice-covered hills are melting into cascades of mud. In some parks, the temperature is rising to above freezing.