By ALEXANDER MARTIN REMOLLINO
MANILA — According to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa), Ondoy brought Metro Manila its highest amount of rainfall in the last 42 years.
“In 1967, a typhoon brought Metro Manila 334 mm of rain in 24 hours,” said Pagasa spokesman Nathaniel Cruz in an interview with Bulatlat. “Last Saturday’s storm brought us the 334 mm of rain in just six hours. ‘Ondoy’ brought us a total of 453 mm of rain in 24 hours.”
Cruz said it may have been “a manifestation of climate change.”
Climate change, however, is not the root: it is itself merely a manifestation of much worse things.
The Fourth Assessment Report of the Nobel Prize-winning Intergovernmental Panel on Climate Change (IPCC), released in 2007, states that human activities have contributed to climate change through increases in the emissions of four principal greenhouse gases: carbon dioxide, methane, nitrous oxide, and halocarbons (a group of gases containing bromine, chlorine, and fluorine).
Carbon dioxide emissions increased from the use of fossil fuels (e.g. petroleum, coal, and natural gas) in the manufacture of cement and other goods, transportation, and building heating and cooling. Decaying plant matter also emits carbon dioxide.
Methane is emitted from landfills, as well as from natural gas distribution and a few activities related to agriculture.
Fossil fuel burning and fertilizer use cause the emission of nitrous oxide. But natural processes in soil and the oceans can contribute to nitrous oxide emission.
Among the principal halocarbons are the chlorofluorocarbons, which have historically been used as refrigeration agents and for other industrial purposes.
Based on the IPCC’s research, the emission of these gases have increased since 1750, or the start of the industrial age, and particularly in the previous century.
Changes in the emission of these principal greenhouse gases affect the presence and amounts of ozone, water vapor, and aerosols in the air.
The increased emissions of carbon monoxide, hydrocarbons, and nitrogen oxide have increased ozone in the troposphere, the atmosphere’s first layer, leading to increase in temperatures in a number of areas. On the other hand, high halocarbon emissions have depleted ozone in the stratosphere (the second atmospheric level), leading to cooling in some areas.
The amount of water vapor in the air is a significant determinant of the general warmth or coolness of an area; more water vapor means a warmer atmosphere. Methane undergoes chemical destruction when it reaches the stratosphere, thus producing water vapor.
Aerosols are small particles present in the atmosphere that vary in chemical composition, concentration, and size.
The burning of fossil fuels and biomass has increased the amount of aerosols with sulfur and organic compounds, as well as black carbon (or soot). Soot absorbs sunlight, causing cooling.
Surface mining and some other industrial activities have increased dust in the atmosphere. Dust reflects sunlight, leading to warming.
The IPCC further stated that carbon dioxide accounts for 80 percent of greenhouse gas emissions, mainly resulting from the burning of coal and crude oil.
Ninety percent of carbon dioxide emission is from countries within the Northern Hemisphere. The Group of Eight (G8) countries – Canada, France, Germany, Italy, Japan, Russia, the UK, and the US – and several other European Union member-countries are historically responsible for 65 percent of carbon dioxide emissions, with the US accounting for 20 percent of emissions in 2003.