Carbon Dioxide and Global Warming
Man Made Greenhouse Gas Emissions Affect Average Temperature Rise
How carbon dioxide has a profound impact on the environment. Increased burning of fossil fuels affects average temperature and is causing an increase in sea levels.
The Fourth Assessment Report (AR4) of the United Nations Intergovernmental Panel on Climate Change (IPCC), issued in November 2007, states “Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic (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”.
This report from the IPCC makes it clear that man made carbon dioxide emission is having a profound impact on the environment thru an increase in sea levels and a dangerous increase in world temperature. It is imperative that such increases in carbon dioxide emissions must not only be stabilized but reduced to avoid the worst effects of global warming.
Carbon Dioxide
Carbon dioxide, a colorless, odorless gas is the main constituent of greenhouse gas. It is part of the natural “Carbon Cycle” of life on earth. Carbon dioxide is emitted into the atmosphere by plants and animals through natural processes such as breathing and decay. It is also emitted by the burning of fossil fuels and volcanic eruptions. The gas is absorbed from the atmosphere by plants for photosynthesis and also by the oceans. Before the industrial revolution carbon dioxide emissions were roughly equal to natural absorption.
Carbon Dioxide Atmospheric Concentrations
As measured by the Mauna Loa Observatory in Hawaii the present day concentration of Carbon Dioxide in the atmosphere averages out at 385 parts per million (ppm). Measurements of atmospheric CO2 concentrations prior to 1958 can be made by analyzing the bubbles in ice at different depths in ice sheets, for instance in Antarctica. According to the IPCC 2007 report these measurements show that there were about 280 parts per million of CO2 in the Earth's atmosphere prior to 1800 AD, at least as far back as 1000 AD.
Average Temperature Rises
The earth receives its energy from the sun. About 30 per cent of sunlight is scattered back into space by the outer atmosphere, but the rest reaches the earth's surface, which reflects it back into the atmosphere as infrared radiation. Carbon dioxide allows direct sunlight to pass through but reflects infrared radiation, thus keeping the heat that would be lost to space within the atmosphere. It acts like the glass roof of a glasshouse, thus the name. The more carbon dioxide there is in the atmosphere, the more heat that is trapped.
Again the 2007 IPCC AR4 report states, “With very high confidence, that the globally averaged net effect of human activities since 1750 has been one of warming.” According to their figures the average temperature of the earth's surface has risen by 0.74 degrees C (1.3 Fahrenheit) since the late 1800s. It is expected to increase by another 1.8° C to 4° C (3.0 to 7.0 Fahrenheit) by the year 2100.
Such increases, even at the low end of the scale would have profound effects on the planet. They would impact on climate, food production, migration, rising sea levels and the ecology of large parts of the world.
Carbon Footprint
Every person and most man made processes produce a carbon footprint. By taking the necessary steps to lower their personal carbon footprint, individuals can do something to help to ameliorate the worst effects predicted by the IPCC.
