Some Possible Effects of a Warmer
World
A warmer global climate could have a number of possible effects.
One is change in food production, which could increase
in some areas and drop in others. In parts of Asia, food production
in more northern areas could increase because of the favourable soils.
However, in North America the northward expansion of crop-growing
regions from the Midwestern United States into Canada would be limited
by the thinner and less fertile soils there. Siberia also lacks rich
soils and couldn't make up for lower crop production in Ukraine.
Global warming could also reduce water supplies
in some areas. Lakes, streams, and aquifers in some areas that have
provided water to ecosystems, croplands, and cities for centuries
could shrink and dry up altogether. This would force entire populations
to areas with adequate water supplies – if they could.
Global warming will also lead to a change in the makeup and
location of many of the world’s forests. Forests in
temperate and sub arctic regions would move towards the poles or to
higher altitudes, leaving more grassland and shrub land in their wake.
Oregon State University scientists in the USA project that drying
from global warming could cause massive wildfires
in up to 90% of North American forests. If widespread fires occurred,
large numbers of homes and large areas of wildlife habitats would
be destroyed. Huge amounts of carbon dioxide would be injected into
the atmosphere, which would accelerate global warming.
Climate changes would lead to reductions in biodiversity
in many areas. Large-scale forest diebacks would cause a mass extinction
of plant and animal species that couldn't migrate to new areas. Fish
would die as temperatures soared in streams and lakes and as lowered
water levels concentrated pesticides. Any shift in regional climate
would threaten many parks, wildlife reserves, wilderness areas, wetlands,
and coral reefs, wiping out many current efforts to stem the loss
of biodiversity.
In a warmer world, water in the world’s oceans would expand
and lead to a rise in sea level. Even the modest
rise of 19 inches projected to occur by 2100 would flood coastal regions
– where about one-third of the world’s people and economic
infrastructure are concentrated – as well as lowlands and deltas
where crops are grown. It would also destroy most coral reefs, move
barrier islands farther inland, accelerate coastal erosion, contaminate
coastal aquifers with salt water, reduce already declining global
fish catches, and flood tanks storing oil and other hazardous chemicals
in coastal areas. If warming at the poles caused ice sheets and glaciers
to melt even partially, the global sea level would rise even more.
In a warmer world, weather extremes are expected
to increase in number and severity. Prolonged heat waves and droughts
could become the norm in many areas, taking a huge toll on many humans
and ecosystems. As the upper layers of sea water warm, damaging hurricanes,
typhoons, tornadoes, and violent storms will increase in intensity
and occur more frequently.
Global warming also poses threats to human health.
According to the 1995 IPCC report, global warming would bring more
heat waves. This would double or triple heat-related deaths among
the elderly and people with heart disease. A warmer world would also
disrupt supplies of food and fresh water, displacing millions of people
and altering disease patterns in unpredictable ways. The spread of
warmer and wetter tropical climates from the equator would bring malaria
and other insect borne diseases to formerly temperate zones. Atmospheric
warming also affects the respiratory tract by increasing air pollution
in winter months and increasing exposure to dusts, pollens, and smog
in summer months. Sea-level rise could spread infectious diseases
by flooding coastal sewage and sanitation systems.
How can we slow possible global
warming?
The diagram below presents a variety of solutions analysts have suggested
to slow possible global warming; none of these solutions are being
vigorously pursued.
The quickest, cheapest, and most effective way to reduce emissions
of carbon dioxide and other air pollutants over the next to two three
decades is to use energy more efficiently.
Some analysts call for increased use of nuclear power because it
produces only about one-sixth as much carbon dioxide per unit of electricity
as coal.
Using natural gas could help us make the 40 to 50 year transition
to an age of energy efficiency and renewable energy. When burned,
natural gas emits only half as much carbon dioxide per unit of energy
as coal, and it emits far smaller amounts of most other air pollutants.
Shifting from high-carbon fuels such as coal to low-carbon fuels such
as natural gas could reduce carbon dioxide emissions by as much as
40%. However, without effective maintenance, more reliance on natural
gas can increase the inputs of methane (a potent greenhouse gas) from
leaking tanks and pipelines, and thus increase global warming.
One method of reducing carbon dioxide emissions would be to phase
out government subsidies for fossil fuels based on their emissions
of carbon dioxide and other air pollutants.
Reducing deforestation and switching to more sustainable agriculture
would reduce carbon dioxide emissions and help preserve biodiversity.
Slowing population growth is also crucial. If we cut per capita greenhouse
gas emissions in half but world population doubles, we’re back
where we started. Some analysts argue that it is vital to global environmental
security that developed countries transfer energy efficiency, renewable
energy, pollution prevention, and waste reduction technologies to
developing countries as soon as possible.
It has also been suggested that we remove carbon dioxide emissions
from the exhaust gases of fossil fuel burning vehicles, furnaces,
and industrial boilers. Some call for a massive global reforestation
program as a strategy for slowing global warming.
