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What Results from Global Warming?

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Atmospheric Temperature Rise Predicted

The Intergovernmental Panel on Climate Change, in which more than 1,000 scientists participate from countries around the world, compiled its second report in 1995. The report states that the average temperature on the earth increased by about 0.3 - 0.6 over the past 100 years, and that global warming will further advance if no new measure is taken, raising the average temperature at the end of the 21st century by about 2 (minimum: about 1; maximum: about 3.5), and further in the future. An increase of 2 is not to be dismissed as "only" 2; the scorching heat wave in Japan in 1994 was, in fact, an increase of "only" 1 from the average year.
Even during the ice age, the average temperature was only 3 - 6 lower than today, which underlines the seriousness of a 2 increase in average temperature.

Effects of Atmospheric Temperature Rise

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Table 1 Area, Population and Assets on Japanese Lowlands Subjected to Sea Level Rise

Unit: area(km2)/Population(10,000 persons)/Assets(trillion yen)

Present Sea level rise 30cm Sea level rise 50cm Sea level rise 1m Area Population Assets Area Population Assets Area Population Assets Area Population Assets Average sea level 364 102 34 411 114 37 521 140 44 679 178 53 Full tide 861 200 54 1192 252 68 1412 286 77 2339 410 109 Typhoon or tsunami 6268 1174 288 6662 1230 302 7538 1358 333 8898 1542 378

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• Impact on water resources and natural disasters
  Global warming accelerates the normal cycle of rainfall and evaporation, destroying balance of water supply and demand and even possibly expanding worldwide gap in water availability. For example, there would be areas that were frequently flooded on one hand, and areas constantly suffering drought and water shortage on the other. In areas which already have a water shortage problem, the situation will worsen; many other areas will face similar problems.
  
  
• Impact on agriculture
  Global warming will seriously affect agriculture as well. Some species of agricultural crops will be adversely affected by higher temperatures, increased weeds and harmful insects. It is also possible that global warming will lead to global food shortages. An investigation conducted by Nagoya University and the National Institute for Environmental Studies predicts that rice production will increase slightly in some countries, but that a substantial drop in output of wheat and corn is likely in major production sites such as China and India. It is estimated, for example, that the production of winter wheat will decrease by 55% in India and 15% in China by the year 2100. This will in turn have serious impact on Japan, which depends heavily on other countries for its food supply.
  In Japan, the impact of global warming is already being seen in the production of rice, the country's stable food, and wheat. While rice harvests are expected to increase in the Hokkaido and Tohoku regions, wheat production is likely to decrease in all regions. It is also possible that global warming will trigger frequent natural disasters, including accelerated activity of weeds and harmful insects, allowing harmful insects from the tropical and subtropical zones to spread to the temperate zone and damage harvests.

• Impact on human health
  Climatic change affects human health in many different ways, most of which are adverse; it is anticipated that climatic change will lead to the loss of many lives. Direct causes of death will include intensified heat waves and diseases. Indirect causes will include expanded geographical sphere of activity of organisms carrying contagious diseases, and their extended period of activity, resulting in an increase in contagious diseases, including malaria, dengue fever and yellow fever. Higher atmospheric temperatures and more frequent flooding are expected to result in higher rates of salmonella poisoning and cholera.
  The negative impact of hot summer weather on the elderly is also worrisome. It is reported that the death rate increases, especially among those aged 65 and above, when the daily maximum temperature exceeds 33.
  
  
• Impact on animals and plants
  Global warming will cause animals and plants to shift their habitats to northern and mountainous areas. It is anticipated, however, that some will become extinct if they cannot migrate due to topographical obstacles, urbanization or habitat changes much slower than climatic changes. It is predicted, for example, that alpine flora growing near mountain summits will become extinct, and that many beech forests will disappear and be replaced by oak forests, which are widely distributed in warm regions. As a result, not only wild animals that live in or feed on these trees, but also fruit cultivation and forestry will be seriously affected.
  Protected zones of flora and fauna demarcated by today's environmental conditions will become inappropriate following climatic changes, and can even accelerate extinction.
  
  
  

Fig. 7 Comparison of Vegetation Zones in Japanese Archipelago under Average and Warmer (21st Century) Climatic Conditions

Data:Grave Impact of Global Warming (Environment Agency)

• Impact on cities
  While winter heating energy consumption will be reduced due to global warming, it will increase for summertime air conditioning. In urban areas, local temperature rise (heat island phenomenon) will increase, due to concentrated energy use, while water use and energy consumption for cooling will also largely increase.