Chapter 8
Because the global climate is a connected system climate change impacts are felt everywhere.
Among the most important climate change impacts are:
Rising Sea Levels
Climate change impacts rising sea levels. Average sea level around the world rose about 8 inches (20 cm) in the past 100 years; climate scientists expect it to rise more and more rapidly in the next 100 years as part of climate change impacts.
Coastal cities such as New York are already seeing an increased number of flooding events and by 2050 many such cities may require seawalls to survive. Estimates vary, but conservatively sea levels are expected to rise 1 to 4 feet (30 to 100 cm), enough to flood many small Pacific island states (Vanatu), famous beach resorts (Hilton Head) and coastal cities (Bangkok, Boston).
If the Greenland ice cap and/or the Antarctic ice shelf collapses, sea levels could rise by as much as 20 ft (6 m), inundating, for example, large parts of Florida, the Gulf Coast, New Orleans and Houston.
Melting Ice
Projections suggest climate change impacts within the next 100 years, if not sooner, the world’s glaciers will have disappeared, as will the Polar ice cap, and the huge Antarctic ice shelf, Greenland may be green again, and snow will have become a rare phenomenon at what are now the world’s most popular ski resorts.
Torrential downpours and more powerful storms
While the specific conditions that produce rainfall will not change, climate change impacts the amount of water in the atmosphere and will increase producing violent downpours instead of steady showers when it does rain.
Hurricanes and typhoons will increase in power, and flooding will become more common.
Anyone in the United States who has tried to buy storm and flood insurance in the past few years knows that the insurance industry is completely convinced that climate change is raising sea levels and increasing the number of major storms and floods. (To understand the insurance industry’s thinking on the subject, consider the chart below compiled by Munich Re-Insurance.)
Despite downpours in some places, droughts and prolonged heatwaves will become common.
Rising temperatures are hardly surprising, although they do not mean that some parts of the world will not “enjoy” record cold temperatures and terrible winter storms. (Heating disturbs the entire global weather system and can shift cold upper air currents as well as hot dry ones. Single snowballs and snowstorms do not make climate change refutations.)
Increasingly, however, hot, dry places will get hotter and drier, and places that were once temperate and had regular rainfall will become much hotter and much drier.
The string of record high temperature years and the record number of global droughts of the past decade will become the norm, not the surprise that they have seemed.
As the world warms, entire ecosystems will move.
Already rising temperatures at the equator have pushed such staple crops as rice north into once cooler areas, many fish species have migrated long distances to stay in waters that are the proper temperature for them.
In once colder waters, this may increase fishermen’s catches; in warmer waters, it may eliminate fishing; in many places, such as on the East Coast of the US, it will require fishermen to go further to reach fishing grounds.
Farmers in temperate zones are finding drier conditions difficult for crops such as corn and wheat, and once prime growing zones are now threatened.
Some areas may see complete ecological change.
In California and on the East Coast, for example, climate change impacts and warming will soon fundamentally change the forests; in Europe, hundreds of plants species will disappear and hundreds more will move thousands of miles.
Changing Fisheries
Shift in Forest Types
California Tree Species Changes
European Species Changes
One of the most striking impacts of rising temperatures is felt in global agriculture, although these impacts are felt very differently in the largely temperate developed world and in the more tropical developing world.
Different crops grow best at quite specific temperatures and when those temperatures change, their productivity changes significantly.
In North America, for example, rising temperatures may reduce corn and wheat productivity in the US mid-west, but expand production and productivity north of the border in Canada.
The productivity of rice, the staple food of more than one third of the world’s population, declines 10% with every 1⁰ C increase in temperature.
Past climate induced problems have been offset by major advances in rice technology and ever larger applications of fertilizer; expectations are that in Thailand, the world’s largest exporter of rice, however, future increases in temperatures may reduce production 25% by 2050.
At the same time, global population models suggest that developing world will add 3 billion people by 2050 and that developing world food producers must double staple food crop production by then simply to maintain current levels of food consumption.
Climate Change and Food Security
Climate Change Impacts on Production
Temperatures and Food Production
