The greenhouse effect is an indispensable natural phenomenon to keep the warmth of the planet’s surface. Without it, Earth would be too cold, around -19ºC. The gases of the greenhouse effect are able to keep the sunlight warmth in the atmosphere, consisting of a kind of blanket around the planet, preventing it from escaping out to space.

Such a phenomenon becomes an environmental problem when the gases of the greenhouse effect (such as carbon dioxide, methane and nitrous oxide) are intensified by human activities, causing an increase in the Earth’s average temperature, known as Global Warming.

The fragile natural balance of climate was affected by the industrial revolution. The average global temperature increased 0.74ºC between 1906 and 2005. The warmest years were 1995 and after. According to research reports by scientists of the IPCC - Intergovernmental Panel on Climate Change (Feb 2007) :
- there are no doubts global warming is caused by human activity;
- The planet’s average temperature will climb between 1.8ºC and 4ºC by 2100 (3ºC average);
- hurricanes and typhoons will be stronger;
- drought areas will be expanded;
- There will be more intense warmth waves, more floods;
- sea level will rise between 20 and 60 centimeters by the end of the century, not considering the probable melting of poles;
- one half of all animal species will be at extinction risk by the end of the 21st century.

The possible impact of global warming in Brazil as foreseen by Brazilian researchers at INPE (Instituto Nacional de Pesquisas Espaciais) :
- In the upcoming years, Southern and Southeastern regions will suffer with increasingly frequent rainfalls and floods.
- The Amazon forest may lose 30% of its vegetal cover due to a temperature increase between 3ºC and 5.3ºC by 2100.
- In the Northeastern, by the end of the century, the variation will be between 2ºC and 4ºC.
- Sea level will rise 0.5 meter in next decades affecting some 42 million people.
- The temperature increase in the Center-South of the country will be between 2ºC and 3ºC, with an increased strength of rainfalls.

The concentration of carbon gas or carbon dioxide (CO2) in the atmosphere has increased especially due to the use of fossil fuels (coal, petroleum, natural gas) in thermoelectric power plants, industries, automobiles and also due to the devastation and burning of forests.
CO2 is the gas that contributes the most to global warming. The carbon gas emitted now will remain in the atmosphere for a long time (around 100 years).

THE MAIN POLLUTERS

The industrialized countries are the main responsible for carbon gas emissions in the atmosphere. Most of the degradation was historically caused by developed countries.
The USA, with 4% of the world’s population, is the responsible for over 20% of all global emissions of greenhouse effect gases.
Through the Kyoto Protocol, an international agreement promoted by the UN in February 2005, several industrialized countries committed to reduce in 5% their emissions of greenhouse effect gases by 2012 based on their emissions in 1990. The President George Bush’s government declined to sign the treaty. Opposing to such a decision, majors from hundreds of US cities committed themselves to reduce their own emissions.

In order to achieve their goals, rich countries can use the Clean Development Mechanism (CDM), which allows for the purchase of “carbon credits” from developing countries, such as Brazil, by adopting projects that surely reduce the emissions of greenhouse effect gases in the sectors of energy, transportation and forestry (considers the forest planting not the conservation of already existing ones).

The developed countries that emitted more carbon gas in 2004 were in order : USA, Japan, Germany, Canada, United Kingdom, Australia, Italy, France, Spain and Poland. The source is the United Nations Framework Convention on Climate Change, official report, 2006. (UNFCCC)

Considering all countries, the main contributors to the greenhouse effect are : USA (20%), China (15%), European Union (14%), Russia (6%), India (5.6%), Japan (4%), Germany (3%), Brazil (2.5%), Canada (2.1%) and England (2%). Source : World Resources Institute (2005).

The global demand for energy is expected to increase considerably in upcoming decades due to the economic growth of China and India, countries that hold some 40% of the world population. Both nations have mineral coal (“dirty” energy) as their main energy sources. An alternative is the development of new technologies using biomass.

Brazil bases its energy production chiefly in hydroelectric power plants (“clean” energy), but when considered all emissions of greenhouse effect gases produced by wild fires and agriculture, Brazil is a main polluter.
The country needs to control deforestation and wildfires. One of the forest functions is to absorb carbon gas from the atmosphere through photosynthesis, promoting carbon sequestration. In Brazil, wildfires in the Amazon account for most gas emissions that cause the greenhouse effect. Such a gigantic region requires conservation measures. When a tree is cut, the carbon gas stocked inside of it goes to the atmosphere.

In the energy sector, Brazil had important initiatives such as the development of the alcohol and bio-diesel program, and also has a large potential for the implementation of solar and wind energy and the use of biomass.

The burning of fossil fuel is the main cause of the increased concentration of greenhouse effect gases in the atmosphere and the impact of global warming that threatens the forests. The warm and dry environment is more vulnerable to wild fires. If the world can not control the emissions of polluting gases, the Amazon forest will collapse. Large portions of the forest will become scrubland (savanna process) causing a tremendous loss of biodiversity.

In the average, each US citizen is the responsible for the emission of about 22 tons of carbon dioxide per year, according to UN statistics, a per-capita figure much larger than that of any other industrialized country, where the average is 6 tons of carbon dioxide per capita.

OTHER GASES OF THE GREENHOUSE EFFECT

Methane, a greenhouse effect gas, is the responsible for one third of the planet’s warming. Its capacity to keep warmth in the atmosphere is 23 times larger than that of carbon gas. About 28% of the world emissions come from cattle raising. Livestock discharge millions of tons of methane every year in the atmosphere (belching, intestinal fermentation, manure). Methane is also produced by burning natural gas, in rice wetlands, in landfills and garbage deposits (decomposition of organic residues), in sewage, in burning coal and other vegetal materials, among others. Methane remains active in the atmosphere for 12 years.
According to a report by FAO (Nov 2006), the livestock sector is more hazardous to environment than transport.

Chlorofluorocarbons (CFCs) produced by the chemical industry are also greenhouse effect gases and destroy the ozone layer that protects Earth from harmful radiation emitted from the Sun that can damage vegetation and cause skin cancer in humans. By means of an international agreement, the Montreal Protocol, determining the elimination of all substances that destroy the ozone layer, CFCs have been banned from refrigerators, air conditioners and sprays. With that global effort, scientists expect the slow recovery of the ozone layer, but the situation in Antarctica has been worsening in last decades.

The average presence of CO2 in the atmosphere measured in 2005 was 35.4% higher than that of pre-industrial times. The concentration of nitrous oxide, in turn, increased 18.2% since the 17th century, especially generated by the burning of fossil fuels, biomass, by the use of fertilizers and in industrial processes. The presence of methane in the atmosphere increased 154.7% since the beginning of the industrial era. The numbers are from a newsletter published by WMO – World Meteorological Organization, a UN specialized agency.

THE PLANET HAS FEVER SYMPTOMS

Record-breaking increase in temperatures, melting of glaciers, sea level elevation threatening coastal cities, desertification, larger number of wild fires, increase in the strength and frequency of typhoons, cyclones and hurricanes due to the warming of ocean waters (such as Katrina that hit New Orleans), among other evidences.  The warming has caused a 20% reduction of the Arctic polar icecap in the past three decades. The Greenland island is losing ice in large scale and ice cracks make the glaciers unstable. Ice blocks by the size of small countries are collapsing into the sea off Antarctica. The Summer 2003 in Europe was the hottest in 500 years and caused thousands of heat-related deaths.

In 2004, a cyclone reached the southern coast of Brazil leaving more than 33,000 people homeless and losses of over R$ 1 billion.
In 2005, the Amazon region suffered from drought caused by increased Atlantic surface temperatures, isolating 35 municipalities. A number of vessels ran aground.

The total number of areas affected by drought doubled in 30 years. Deserts advance. British scientists of the Hadley Institute predict that one third of the planet will be desert by 2100.

Air pollution especially caused by fossil fuel burning kills 2 million people per year, according to WHO – World Health Organization.

Oceans absorb one third of the carbon gas we release in the atmosphere and are becoming more acid, threatening corals and the marine biodiversity.

Climate effects tend to become increasingly frequent and extreme.
The increased warming may have other consequences : wildfires difficult to control, alteration of rainfall regimes, sea advancement over rivers and shorelines, drinking water scarcity, wildlife habitat destruction and the consequent loss of biodiversity (accelerated extinction of species affecting ecosystems), agricultural losses, more famine, migrations of vulnerable communities (social problems) and human health problems (dengue, malaria, malnutrition, waterborne diseases).

In the movie "An Inconvenient Truth" released in 2006, Al Gore (USA) advises that humanity is sitting on a time bomb. He says that we have only ten years left to avoid an enormous catastrophe that can modify the entire climate system of our planet and result in an epic destruction - a catastrophe created by ourselves.
The film shows that the CO2 concentration in the atmosphere is higher than in any other moment of the last 600 thousand years. Studies demonstrate that high carbon gas concentrations are followed by hot periods in the planet.

The lack of initiative will cost the world economy between 5% and 20% of the Gross Domestic Product, while reducing CO2 emissions now would represent only 1% of GDP, according to the Stern Report, of the British government. If climate change is ignored, it may cause an economic catastrophe compared to a world war.

The problem requires changes in many consumption habits. Citizens around the world, as voters, have the power to pressure the governments to impose limitations in emissions and to adopt renewable energy sources. Earth cries for help. We have to act now. Urgent measures can not be postponed.

Learn More : Mercado Carbono, Ministério da Ciência e Tecnologia MCT (Protocolo de Kyoto), CPTEC,   Ambiente Brasil, WWF e Green Peace.

Videos.

Tips to reduce air pollution and the impacts of climate changes

www.natureba.com.br On-line Environmental Education for All