Green House Gases

Humans have changed planet earth. One of our accomplishments is to extract and burn much of the fossil fuel deposits on the planet. We have increased the concentrations of greenhouse gases in the atmosphere and are now observing the changes in weather patterns and climate that are a result of our actions.

Greenhouse gases are carbon dioxide, methane, nitrous oxide, hydrofluorocarbon chemicals, and chlorofluorocarbons. These gases act like the glass covering a greenhouse, letting sunlight in but blocking some of the infrared radiation from the earth's surface that carries heat back into space. The gases act like a blanket wherever their concentration increases. Local concentrations increase local heat and increased differences between hotter and colder regions drives weather events into more extreme ranges.

The planet's thermostat had been set at a pleasant average temperature of 59 degrees (F) for the last 10 thousand years or so and is now undergoing a rapid change. Global warming means that the earth retains more of the sun's heat over time. The warming effect of greenhouse gases is reduced by particle pollution and clouds that block incoming infrared radiation. Without particle pollution, ice crystals and water vapor in the atmosphere, global warming would be more rapid.

The attempt to understand complex systems has taken a quantum leap in recent years. We have gone beyond naïve linear models and now appreciate that if complex systems such as the atmosphere, the oceans, and land ecosystems change, they become unstable, climates change and human habitats that once were stable, become unfriendly or, worse, uninhabitable. Extra heat will cause more turbulence and weather patterns will change in unpredictable ways.

The development of a renewed "green movement" in the media suggests that this is a relatively new concern and people who have ignored climate changes during the past 30 years have had legitimate doubts. The fact is that some know what is really going on out there, but most people do not know or know but deny the obvious for selfish reasons.

Carbon dioxide is the most important gas and is produced from the burning of fossil fuels, and the burning of forests. The concentration of CO2 was 280 PPM before the industrial revolution and now is over 350 PPM. The 1990s, the US produced 23% of global CO2 emissions, Western Europe 14%, former Soviet bloc 20 %, India 4% and Japan 5%. High emission countries pump out over 3 metric tons per capita - the US produces 5.2 metric tons per person. In 2007, China matched emissions typical of the US. Low emission countries produce less than 1 metric tone per capita. Most of Africa, South America, and Asia are below 1 metric ton per capita. If you include Brazil, Indonesia and Germany in the industrial heavy-weight polluters, they account for 56 % of the world's population, 59% if its economic output, 58 % of its carbon-dioxide emissions and 53% of its forests.

Methane is less abundant but traps more heat than carbon dioxide. Methane emissions are about 550 million tons per year from biomass decomposition in wetlands, rice farming, ruminant animals and landfills. Methane is "natural gas" and some enters the atmosphere during its commercial distribution and use as a fuel. Large reservoirs of methane also are found in the arctic and in marine sediments, as methane hydrates. Each methane molecule is encased by water ice molecules. There is speculation that large volumes of methane may be released as ocean temperatures rise and accelerate global warming.

Nitrogen oxides, like hydrocarbons, are precursors to the formation of ozone and contribute to acid rain. Catalytic converters in car exhaust systems break down heavier nitrogen gases, forming nitrous oxide (NO2) - 300 times more potent than carbon dioxide as a greenhouse gas. Nitrous oxide makes up about 7.2 percent of the gases that cause global warming. Vehicles with catalytic converters produced nearly half of that nitrous oxide. Nitrous oxide also comes from nitrogen-based fertilizers and manure from farm animals.

Hydrofluorocarbon chemicals (HFCs) Refrigerants designed to protect the ozone layer have become a major contributor to global warming. Hydrofluorocarbon chemicals (HFCs) were developed to phase out ozone-depleting gases but they are more potent than carbon dioxide as greenhouse gases. A study at the Netherlands Environmental Assessment Agency suggested that HFC emissions will have the heat trapping effect up to 8.8 billion tonnes of carbon dioxide annually by 2010. (G. J. M. Velders et al. Proc. Natl Acad. Sci. USA doi:10.1073.pnas.0902817106; 2009).

The reduction in forest biomass and the exposure of ocean plankton to increase UV radiation are also concerns. Ocean phytoplankton supplies up to 70% of the oxygen we breathe.
The Intergovernmental Panel on Climate Change (IPCC),a United Nations body won the 2007 Nobel Prize for its efforts to boost understanding of climate change. The IPCC Fourth Assessment Report: Climate Change 2007 consists of four reports, three of them from its working groups.

The Physical Science Basis of Climate Change Key Points are:

Warming of the climate system is unequivocal.

Global atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values over the past 650,000 years.

Most of the observed increase in globally averaged temperatures since the mid-20th century is likely due to the observed increase in human greenhouse gas concentrations.

Anthropogenic warming and sea level rise would continue for centuries due to the timescales associated with climate processes and feedbacks, even if greenhouse gas concentrations were to be stabilized soon, although the likely amount of temperature and sea level rise varies greatly depending on the fossil intensity of human activity during the next century . The probability that this is caused by natural climatic processes alone is less than 5%.

World temperatures could rise by between 1.1 and 6.4 °C (2.0 and 11.5 °F) during the 21st century:

Sea levels will probably rise by 18 to 59 cm (7.08 to 23.22 in)

There is a confidence level >90% that there will be more frequent warm spells, heat waves and heavy rainfall.

There is a confidence level >66% that there will be an increase in droughts, tropical cyclones and extreme high tides.

More than thirty years ago, Loren Eisely reflected:

Every Civilization, born like an animal body has just so much energy to expend...space and time widen to weariness. In the midst of triumph, disenchantment sets in among the young. It is as though with the growth of cities an implosion took place, a final unseen structure, a spore-bearing structure towering upward toward its final release. I am one of the world-eaters in the time that my species has despoiled the earth and is about to loose its spores into space. When the swarming phase of our existence commences, we struggle both against the remembered enchantment of childhood and the desire to extinguish it under layers of concrete and giant stones. Like some few persons in the days of the final urban concentrations, I am an anachronism, a child of the dying light.""

Loren Eisely The Invisible Pyramid. 1970