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Human activities build disturbing climate changes

A POINT OF AWARENESS - Preciosa S. Soliven - The Philippine Star

(Part II of “Mapping the World’s Climate Change”)

The orbiting of planet Earth on its side is causing great changes in solar and lunar energy affecting human life and the biosphere (living creatures on land, water and air). In addition, people do not completely understand how modern technology in food production, transportation, and water system have added to the environmental problems.

How transportation aggravates greenhouse gas emissions

International trade, travel and a growing dependence on motor vehicles make transportation one of the main sources of greenhouse gas emissions. Passenger car and truck travel, shipping, and air traffic are all increasing. Worldwide, the transport sector emitted 36 percent more greenhouse gases in 2000 than in 1990. Total passengers journey worldwide via air travel is predicted to reach 4.72 billion by the end of 2020. Cars and trucks accounted for 70 percent of transportation-related greenhouse gas emissions in 2003.

Food security

Climate change threatens food security, although crop yields in temperate regions may improve. Agriculture is highly adaptable. Crop calendars can be adjusted to avoid extreme hot periods, new varieties of plants can tolerate a range of conditions, and good soil management can overcome water stress. With economic incentives, world food production should not be adversely affected by climate change over the next 50 years or so.

Agriculture accounts for about a third of global emissions of CO2 greenhouse gases, methane and nitrous oxide, but in many developing countries it is the main economic activity of the rural population. It is essential to meet basic needs: food, employment and income.

Threats to health

Climate change threatens human health. Where people are already vulnerable to disease as a result of poverty and malnutrition, even small changes in climate may have an effect on health. The poorest regions are likely to be the hardest hit.

Rainfall, temperature, and humidity have a major influence on the distribution of disease pathogens and pests. Warmer temperatures, longer growing seasons, the absence of pest-killing sub-zero temperatures, and increased rainfall all extend the habitat ranges for diseases, as well as for insects, rodents and other organisms that carry them. Climate changes will favor the spread of diseases into previously unaffected areas.

While fewer people may die from cold, warmer weather may lead to increased heat stress. It may also lead to higher levels of air pollutants from forest fires in rural areas, including the formation of volatile organic compounds and ozone in the urban areas. Ozone in the upper atmosphere protects against harmful types of UV radiation. However, at ground level it is a pollutant and can be harmful to health. Thus the number of deaths related to respiratory conditions will rise.

Flooding increases the risk of waterborne diseases such as cholera, typhoid, and dysentery, as well as mosquito-borne diseases, including malaria and yellow fever. The cumulative effects of environmental stresses, including malnutrition, further reduces the ability to fight off infections.

Threatened water supplies

Water is a vital resource and is often taken for granted. With population increasing in some regions and a rising demand for water to irrigate crops throughout the world, water supplies are already a cause for concern in many countries. It is not apparent that climate change might make the situation worse.

An increase in temperature makes surface water evaporate more quickly, reducing supply and increasing demand, especially for water to irrigate crops. Warmer and longer summers also cause snow packs and glaciers to melt more quickly. More rapid melting increases river flows in the spring, but may reduce summer flows. Over the long term, a reduction in snow and ice may seriously threaten many river basins.

If water supplies fail completely, contaminated water, lack of hygiene and thirst will take their toll. Many of the effects of climate change can be countered by prioritizing the most urgent uses, adopting water-saving technology and more efficient irrigation methods. However, less developed countries in drier parts of the world, which lack the technology and infrastructure to effectively manage their water resources, will suffer most.

Renewable energy to adapt to change

Increasing the use of renewable energy sources is an important way of reducing greenhouse gas emission, while continuing to provide power. It could be the technological key to economically and socially sustainable societies.

SMALL-SCALE HYDRO. Hydro systems generate electricity from running water. They can provide power for isolated villages, or feed power into the electricity grid. Small-scale hydro does not involve artificial reservoirs, and so avoids the formation and release of methane from decaying biomass. BIOMASS. Plant material – purpose grown or waste can be burned or fermented and used to generate electricity or heat. The CO2 released is the same amount as was removed from the atmosphere during the plant’s lifetime, so biomass is considered carbon neutral. GEOTHERMAL. In geologically active areas, the Earth’s intense heat can fuel power plants. Elsewhere, its temperature which remains constant at 1.5 meters below the surface, can be used to heat and cool buildings. SOLAR. Photovoltaic panels convert the sun’s radiation into electricity. Thermal panels convert the sun’s radiation into heat. WIND. Wind turbines of varying sizes are used to generate electricity for the national grid or for isolated communities. TIDAL WAVE, OCEAN. The movement of the sea can be used to generate electricity.

Local commitment to climate/disaster management

Most countries have acknowledged the problem of changing climate by signing the Convention on Climate Change. However, in many places, local and regional authorities are developing more aggressive emission reduction policies than federal governments. Cities around the world are now waiting for the national governments to debate its implementation. They have signed their own commitment, as part of the campaign Cities for Climate Protection.

In the USA, mayors urged the national government to slow the rate of global warming. In February 2005, the mayors of Seattle issued a Climate Protection Agreement, pledging to curb the greenhouse gas emissions at the local level. The agreement was endorsed by the US Congress of Mayors and by May 2006, 230 mayors had signed up.

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