Tuesday, June 9, 2009

Debunking CO2 Myths and The Science of Climate Change

There are a number of myths about CO2 that continue to circulate despite scientific evidence to the contrary. These myths are often perpetuated by the uninformed or those with an agenda to protect non-sustainable corporate interests. With the aim of exposing some of the major fallacies here is quick summary of the science debunking eight CO2 myths.

Myth # 1 : CO2 Levels are Not Rising

Objective measurement of atmospheric increases in carbon dioxide was confirmed beginning in the 1930s, and these observations were corroborated in the late 1950s with the development of highly accurate measurement techniques.

In 1959 Charles Keeling began collecting flasks of air from an observatory at the summit of Mauna Loa in Hawaii in 1959. His research, known as the Keeling Curve, confirmed suspicions that carbon dioxide released from the burning of fossil fuels and other industrial activities are accumulating in the atmosphere.

Keeling's data set was confirmed by the Vostok ice core. The ice core findings reveal annual layers of air bubbles trapped in the ice, they can be dated and CO2 levels can be measured representing the atmosphere when the ice formed. Atmospheric CO2 concentrations calculated from trapped air bubbles indicate that "present carbon dioxide concentrations far exceed all values for the past 400,000 years."

Another source of scientific evidence comes from Houghton and Hackler. Their research indicates that land-use changes from 1850-2000 and the combustion of fossil fuels have caused the atmospheric CO2 concentrations to rise from 288 ppmv in 1850 to 369.5 ppmv in 2000. The Mauna Lao Observatory reports that as of May 2009, CO2 levels are at 390 ppmv.

Myth # 2 : CO2 is Not Related to Global Warming

The Vostok ice core reveals ratios of oxygen isotopes and deuterium they in turn indicate air temperature at the station at the time ice was formed. The study shows that carbon dioxide and temperature are linked through feedback loops; when the concentration of CO2 is high so is the temperature.

Myth # 3: CO2 is Not the Most Important GHG

Although water vapor is the most significant GHG, CO2 levels are steadily increasing while others like Methane have stabalized. Human activity is producing levels of CO2 that are upsetting the natural greenhouse balance and imperiling our planet. This is largely because CO2 remains in the atmosphere for more than a century while water vapor lasts only a few days. CO2 is the greatest concern because it is responsible for two-thirds of the additional warming caused by all the anthropogenic GHG.

Myth # 4: Anthropogenic CO2 is Harmlessly Absorbed

The Keeling Curve indicates that carbon dioxide released from the burning of fossil fuels and other industrial activities are accumulating in the atmosphere rather than being fully absorbed by the oceans and vegetated areas on land.

Houghton and Hackler's research has revealed that approximately 40% of the additional carbon has remained in the atmosphere, while the remaining 60% has been transferred to the oceans and terrestrial biosphere. This research reveals that 64% can be attributed to fossil-fuel combustion, representing about 14% of the carbon in the atmosphere in the form of CO2.

According to research from Woods Hole Oceanographic Institution, "around 30 per cent of the CO2 put into the atmosphere by human activities is absorbed by the oceans where it dissolves, altering the chemistry of the surface sea levels making it more acidic." Increasing levels of ocean acidity could destroy fisheries and damage coral reefs that provide habitat and coastal protection from storms. In a statement from the science academies of 70 countries rising levels of CO2 may cause an "underwater catastrophy.

Myth # 5: CO2 is Too Heavy to Reach the Troposphere

According to the Carbon Dioxide Information Analysis Center (CDIAC), the chemical formula of CO2 is Carbon (12) + Oxygen (16) + Oxygen (16), giving it a molecular weight of 44. Although this gas is heavier than air (50% heavier or 1 and 1/2 time as heavy). CO2 will mix with the air as all gasses do because of Brownian Motion (molecules bumping into each other). And like all gases, when wind is blowing, CO2 is carried up into the atmosphere, where more winds are able to carry it up to the troposphere.

"Free radicals, which are atomic or molecular species with unpaired electrons, and are highly reactive and this makes them able to form a chemical bond. The free radicals attach and form a new bond with CO2 creating a new gas depending on the species of the free radical. These gases work their way a bit further into the upper atmosphere and this is where they become GHGs."

Myth # 6: Respiration is to Blame for CO2

All living things including plants and animals exhale CO2. According to the Carbon Dioxide Information Analysis Center (CDIAC), "the average person exhales approximately 1 kg of CO2 per day. However the exhaled CO2 includes carbon that was originally taken out of the carbon dioxide in the air by plants through photosynthesis - whether you eat the plants directly or animals that eat the plants. Thus, there is a closed loop, with no net addition to the atmosphere. Of course, the agriculture, food processing, and marketing industries use energy (in many cases based on the combustion of fossil fuels), but their emissions of carbon dioxide are captured in our estimates as emissions from solid, liquid, or gaseous fuels."

Myth # 7: Technologies Using CO2 are to Blame

According to the CDIAC, technologies that use CO2 are not responsible for increased GHG emissions. Technologies like dry ice blasting, supercritical cleaning and painting etc., do not increase GHG emissions because "most of the CO2 used in these kinds of applications is recovered from processes like fermentation and it is either CO2 that it is being extracted from the atmosphere by plants or CO2 that would have been released from fossil fuel burning anyhow. In essence it passes through this kind of use rather than being emitted immediately and there is no extra CO2 produced".

Myth # 8: Managing CO2 is Too Expensive

There are viable ways we can facilitate the shift towards a low carbon economy. As we will review in the next post, cap-and-trade legislation is a viable way of creating incentives for lowing carbon and generating revenues that can help to finance the transition. Immediate action is required as we simply cannot afford to continue to ignore the cost of anthropogenic CO2 emissions.

Next: Action on Climate Change

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Friday, June 5, 2009

Primer on CO2 and Other GHGs

Carbon dioxide (CO2) is at the center of efforts to manage climate change. Many identify CO2 as the leading cause of calamitous environmental destruction, but how does this naturally occurring substance wreak such havoc on our environment?

For over 100 years the scientific community has been warning us of the dangers of global warming caused by CO2 emissions from fossil fuels. In 1896 S. Arrhenius, published the paper "On the influence of carbonic acid in the air upon the temperature of the ground." More recently a plethora of scientific studies have corroborated these early concerns. (In a forthcoming post we will review some of the scientific evidence for global warming).

CO2 and Other GHGs

CO2 is a naturally occurring chemical compound. CO2 is part of the respiration of plants and animals and it is produced through the decay of carbon based material from plants and animals. Some natural processes, such as volcanoes and geysers, also add CO2 to the atmosphere.

Although CO2 gets most of the attention there are other naturally occuring greenhouse gases (GHGs). Water vapor is by far the most important GHG. It evaporates mostly from the ocean, and it causes earth's surface to be about 30°C warmer (out of the 36°C of warming caused by all greenhouse gases combined). Methane is produced by bacteria in wetlands and bogs, cattle, rice paddies, termites, landfills, and coal mining. Nitrous oxide is produced from microbes in the soil and the ocean. Halocarbons such as refrigerants are used in air conditioners and tropospheric ozone, produced in smog.

The Greenhouse Effect

Naturally occuring GHGs like CO2 warm and regulate the earth's temperature through the greenhouse effect. Warming occurs because the GHGs, although transparent to incoming solar radiation, absorb infrared (heat) radiation from the Earth that would otherwise escape from the atmosphere into space. GHGs re-radiate some of the heat back towards the surface of the Earth.

Normally almost half of energy emanating from the sun is trapped in our atmosphere. This natural phenomenon is what we call the greenhouse effect, GHGs warm the earth so that it is conducive to life, if there were no GHGs the temperature on earth would fall below –18 C.

GHGs and Global Warming

The unnatural addition of GHGs to the atmosphere is known as global warming. This unnatural build-up of GHGs in the troposphere (the lower part of the atmosphere about 10-15 kilometres thick) is trapping additional heat. The amount of heat in the troposphere depends on concentrations of GHGs and the amount of time these gasses remain in the atmosphere. CO2 remains in the troposphere between fifty and two hundred years.

CO2 and Human Activities

Anthropogenic (human-produced) CO2 is mixing with naturally produced CO2 and influencing the earth's radiation balance. The two main human activities that increase the amount of carbon dioxide in the earth's atmosphere are fossil fuel burning and land clearing. The burning of fossil fuels adds about 6 gigatons of carbon to the atmosphere each year.

Prior to the industrial revolution, atmospheric CO2 concentrations had not changed appreciably for over 850 years. That changed around 1850 when human processes began emitting significant quantities of GHGs. Pre-industrial levels of CO2 were approximately 270 and according to scientists at the Mauna Loa observatory, as of 2008, CO2 levels in the atmosphere were at 387 parts per million (ppm). This represents an increase of approximately 40% since the industrial revolution and the highest levels of CO2 in at least 650,000 years.

The US national oceanic and atmospheric administration research has corroborated other findings that indicate CO2 is accumulating in the atmosphere faster than expected. Their review suggests that levels of CO2 emmisions are on the increase, from 1970 to 2000, the concentration of CO2 rose by about 1.5ppm each year, but since 2000 the annual rise has surged to an average 2.1ppm. "Researchers suggest the trend could mean that the earth is losing its natural ability to absorb billions of tonne of CO2 each year."

CO2 emissions from cars and industry are a major cause of what we refer to as global warming. These increasing CO2 emissions cause about 50-60% of the global warming. Human activities have released an amount of CO2 that exceeds the amount sequestered in biomass, the oceans, and other sinks. About 22% of the current atmospheric CO2 concentrations exist due to these human activities. Fossil fuel combustion for energy generation causes about 70-75% of the anthropogenic CO2 emissions. The remaining 20-25% of the emissions are caused by land clearing and burning and by emissions from motor vehicle exhausts.

Other GHGs Associated with Human Activity

According to Ocean World, about two thirds of the methane emissions into the atmosphere come from human activity, mostly from the northern hemisphere. Methane concentration was 1783 parts per billion in 2004, which was 155% larger than pre-industrial concentrations. The rise in methane appears to have leveled off, and concentrations have increased only 5 parts per billion since 1999. Methane does not remain long in the atmosphere, about 8 years (Fischer et al, 2008). However methane is 22 time more effective in absorbing infrared radiation than CO2.

Nitrous oxide (N2O) is also a byproduct of burning fossil fuels at high temperatures. About one-third of the emissions into the atmosphere come from human activity. N2O concentrations were 319 parts per billion in 2004, which was 18% larger than pre-industrial concentrations. Its lifetime in the atmosphere is about a century.

US GHG Emissions

Although the US is only 4.6% of the world's population, American energy use accounts for 24% of all the world's energy. According to the Statistical Review of World Energy 2005 89.4% of energy consumption in the US is derived from burning fossil fuels.

The average American uses almost 31 kilowatt-hours (kWh) per day, or 1.3 kilowatts (kW) continuously. Most of that electricity is produced by burning fossil fuels. In certain other fully modern countries (England, France, Germany, Japan), the per-capita average ranges from 0.6 to 0.8 kW. At the other end of the scale, in developing countries where, even if some cities are electrified, rural areas are generally without power, the number is much lower: Mexico uses 0.14 kW, Thailand 0.10, and Peru 0.05. India is way down, at 0.037. China is around 0.07.

While most GHG emissions derive from industrial processes in developed countries like the US, GHGs from developing countries are rising. At the current rate, anthropogenic carbon dioxide emissions are expected to double in this century.

GHGs contribute to the greenhouse effect and many anthropogenic GHGs are on the increase. In the next post we will review the effects that they are having on the earth and its inhabitants.

Next: The Effects of Global Warming / Debunking CO2 Myths and the Science of Global Warming / Action on Global Warming.

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