The biological components of our environment have evolved in harmony with the physical and climatic surroundings. The presence, characteristics, structure and behavior of both individual organisms and co-assemblages, or communities, of organisms are largely determined by climate. The ability of natural communities to adapt to changing climate, and nature of community change is of utmost importance to the survival of man.
As discussed in "Currents" a change in the air-sea current system can result in significant changes in regional climates. Regional climates shifts may include temperature extremes, averages and seasons; while precipitation amounts, intensities and seasonal distribution may be altered along with wind intensities and patterns. Generally we can expect to experience greater variability, and an increase in violent, or extreme, weather events. The impact of regional climate changes is extraordinarily complex and has received little attention. While a warming environment might be considered beneficial, there will be substantial negative impacts upon our civilization. Economics, agriculture, infrastructure, health and "quality of life" will be effected in a largely unknown manner. Do we have the means, will, and wisdom to determine the potential impacts of regional climate change, and to prepare for them?
The landscape, or vegetation, that surrounds us has both evolved and migrated in response to the stresses of past climatic changes. The fossil records show us species that no longer exist, and species that now only exist in other locations. The actual migration rates of plants largely unknown, but are obviously slower than that of animals and vary by species. A number of factors would effect the migration rate of a plant species, including age to reproduction, and means of seed dissemination. Additionally, plant seeds often require specific conditions for germination and growth. Thus the ability of plants to migrate in response to a rapidly changing climate can only be a source of speculation at this time. In addition to supporting such human activities and forestry and agriculture, the landscape is also habitat for both wildlife, including disease vectors. Historically, human life has been closely tied to the landscape; do we have the capability to adapt our cultures, economies and life styles to changing landscapes?
The ability of a biological community to adapt to a changing climate requires a flexibility, or plasticity, requires genetic diversity and a variety of species, collectively termed "biodiversity". World-wide governments and the scientific community recognizes The World Conservation Union's (ICUN) "Red List of Threatened Species" as the ultimate authority. The 2007 List was recently released with these words: "Life on Earth is disappearing fast and will continue to do so unless urgent action is taken. There are now 41,415 species on the IUCN Red List and 16,306 of them are threatened with extinction, up from 16,118 last year". While climate induced stress is not the major cause of all extinction, the IUCN states that: "99% of threatened species are at risk from human activities". Do we have the will to reduce this loss of biodiversity that will be required for our natural surroundings to adapt to climate change?
The loss of biodiversity includes the loss of wildlife. Perhaps nowhere is this loss more acute, and its importance to mankind greater, than in the oceans. Ocean temperatures, current patterns, salinity, and acidity all impact aquatic life, and each of these factors is being altered by the increase in atmospheric CO2. The threat of climate change to the worlds fisheries, and thus the nourishment of millions of people is enormous. As the increase of ocean temperatures and acidity will continue until the CO2 levels in both the atmosphere and the oceans stabilize, maintenance of fishery resources appears highly unlikely. Do we have the will and capacity to replace the economic consequences due to the loss of the fishery industry, and to provide nutrition to those who depended upon the resource?
World-wide, agriculturists , foresters, gardeners and bee-keepers are observing changes in growing seasons, and species responses to a changing environment. It is reported that apples are being grown in Anchorage , Alaska (AP. Climate change challenging gardeners to plant smarter. 2007) Bee-keepers are reporting flowers blooming a month earlier than they did in the 1970's (The Washington Post. Weather may account for reduced honey crop. Sept. 10, 2007) while viticulturists in north France are harvesting grapes two months earlier (Washington Post Foreign Service. In northern France, warming presses fall grape harvest into summertime. Sept. 2, 2007). In the United States, multi-year droughts in the southwest and south east regions (which have consistently been predicted by climatic models) are having severe impacts upon agriculture. As a general warming trend moves northward, new agricultural pests are following, invading regions where they had previously been killed by harsh winter conditions. Relationships, that have evolved for centuries, between pollinators and plants are being disrupted as the plants flower before migrating pollinators arrive. What is the future of our agricultural system? Can we accommodate changing land use patterns? Do we have the ability to reclaim lands abandoned by agriculture due to climate change, and/or salinization? In view of climate induced changing agricultural patterns does the system have the added capacity needed for capacity for biofuel production?
Regional climate change is currently causing shortages of fresh water throughout the world. The situation will rapidly worsen as the equatorial glaciers melt in Africa and they Himalayas. It is widely predicted that many glaciers will disappear within 30 years, and the rivers that they feed will either dry up or have substantially reduced flows. Millions of people in Africa, China and the Indian Sub-continent face severe water shortages. Elsewhere, Australia is experiencing an historic multi-year drought, while periods of water rationing has been imposed throughout the northern hemisphere. Do we have the will, or capability to conserve fresh water, and distribute it to areas of shortage? Will, and can we accommodate drought refugees? Do we have the will, and capability to provide food, health care and other needed aid to drought stricken regions of the world? Do we have the will and capabilities to prevent "water wars"?
Sea levels are gradually rising throughout the world, primarily due to thermal expansion as the oceans warm, and to the increased input from melting glaciers. It is vital to recognize that these processes would continue for thousands of years after a complete elimination of CO2 emissions. Since arctic ice is already floating in the ocean, its melting will not directly increase sea levels. However, the reduction of reflectivity as ice melts results in greater absorption of energy which warms the ocean and increases thermal expansion. Historically, settlements were concentrated along coasts, and the sea provided both transportation and nourishment. This trend continues today, with a large percentage of the worlds population concentrated in coastal regions. As sea levels rise, these populations will be displaced. Also at risk is the physical infrastructure of coast cities and ports. The ice sheets on Greenland and Antarctica each contain enough fresh water to raise ocean levels in excess of 20 feet (18m). The ice sheet over Greenland averages over 1 mile thick (2km) is rapidly melting along the coast, and in the past few years its glaciers have gained speed. Due to the thickness of the ice, we do not have an good description of the underlying bedrock and how ice would move over the surface. However, we do know that the structure of the ice sheet is changing, and that a great deal of melt water appears be moving underneath the ice. If this ice sheet were to suddenly collapse, the sea level would rise approximately 20 feet (18 meters), millions of people would be displaced, the ocean conveyor system would most likely halt causing an abrupt climate change in the northern hemisphere, and the rising sea levels would flood the bottom of the West Antarctica Ice sheet (which is just above sea level) which would add enough ice to the ocean to raise its level another 20 feet. While this scenario is not considered highly probably, it is recognized a possibility since we do not understand the current ice behavior in either Greenland or Antarctica. Do we have the will and the wisdom to accommodate the inevitable increase in sea levels in our coastal infrastructures and to control future coastal development?