[click on the title above to hear the 15 minute audio broadcast]
SAY HELLO TO METHANE – THE AMERICAN QUICK FIX FOR GLOBAL WARMING
From Radio Ecoshock, www.ecoshock.org.
The United States, the world’s largest source of human-made greenhouse gases, has ditched global efforts to control carbon dioxide pollution. Instead, following an alternative suggested by top NASA scientists, including James Hansen, America has developed a plan to control trace gases in the atmosphere, principally methane.
American scientists now claim that methane, as a greenhouse gas, and as a chemical agent that produces more harmful ozone, itself a greenhouse gas – may account for up to 30 percent of climate change. Through the EPA, the administration has set up a program to capture waste methane from landfill sites, coal mines, and other sources. Their Plan B for trace gases, the only plan to save the planet’s climate implemented by this administration, has been expanded to include about a dozen other countries – but not the top methane emitters.
Politically, the methane control plan has many advantages for the Bush administration. It leaves the oil companies and coal mining companies free to add unrestrained carbon to the atmosphere. Methane can be re-used as a valuable energy source when captured. And most human-induced methane comes from other less developed countries, instead of the United States. The onus for climate control falls on the major emitters, China, Russia, India, and Brazil.
Even if the plan makes scientific sense, it seems destined for failure in the realities of less developed countries with few resources. Still, the Methane to Markets Partnership is the only plan the United States, and now other countries like Canada, have in play. So we need to examine their claims that global warming and smog can be combated with the same program.
To understand what is being proposed, and whether it will save us, we need to educate ourselves about methane. We need to understand how this gas leads to chemical reactions in the atmosphere that is already killing millions of us by ground-level smog, and threatening all of us, by providing from 20 to 30 percent of the warming in our atmosphere.
Welcome to our rapid-fire methane primer. It’s the introduction to our second part in this series, the justification and evaluation of the trace gas control proposal emerging in many countries. We call that “the methane fix.”
WHAT IS METHANE?
Methane is an odorless gas at normal temperatures on Earth. Gas companies add a sulfur compound to let people know when it is leaking. Chemically, it is made up of one carbon atom attached to 4 hydrogen atoms, or CH4. Methane is the main ingredient of natural gas, which we burn in home heating, electricity production, and even to power automobiles.
When we burn methane, in the presence of oxygen, energy is released along with one molecule of carbon dioxide, and two molecules of water. That’s less carbon dioxide that when oil or coal is burned, so methane gas is considered a cleaner burning fuel, from the perspective of climate change gases – but it still releases CO2 into the atmosphere.
Compared to other gases like nitrogen or oxygen, methane is fairly rare. In every ten million molecules of air, about 16 are methane. Yet on other planets, such as Saturn’s moon Titan, methane is the dominant gas.
Methane itself is not toxic, but it is very explosive. Such explosions are the number one cause of the numerous deaths that occur during coal mining all over the world. There are also risks of natural gas explosions.
As natural gas, methane is difficult to transport long distances because it is so bulky. Other than pipelines, we would need gigantic containers to move it as a gas. The gas can be compressed if it is liquefied, at a temperature hundreds of degrees below zero. We call this Liquefied Natural Gas, or LNG.
METHANE AS A GREENHOUSE GAS
Scientists agree to measure the global warming potential of a gas by comparing it to a molecule of carbon dioxide, over a period of 100 years. By that measure, methane has 21 times the global warming potential of CO2, according to the EPA (other estimates vary slightly). A single molecule of methane will heat the Earth as much as 21 molecules of carbon dioxide. It is a powerful greenhouse gas.
Some sources say methane has doubled since the industrial age began in 1750, others say it has increased by 150%. Studies in ice cores show current methane levels are higher than at any time during the past 400,000 years.
Some scientific studies, done by Dickinson, Cicerone, and Ramanathan, estimate the heating impacts of methane in the atmosphere to be about half the amount generated by carbon dioxide. Others say methane is responsible for only 20% of global warming. The question is made more complicated by the fact that fossil fuel burning, the major source of CO2, also emits pollution particles that cool the Earth at the same time. More on this later.
Methane is recognized by the Kyoto Protocol as a greenhouse gas that needs to be controlled. Since methane is at least 20 times more powerful than CO2, removing 1 ton of methane is as good as removing 20 tons of CO2.
WHERE DOES IT COME FROM?
Methane is produced naturally on the planet from a variety of sources. Some rises from the Earth itself through mud volcanoes. The science of Earth bound methane is not fully understood yet.
We do understand how methane is produced by the plant world. When plant material rots without oxygen around, different bacteria are involved. That’s called anaerobic decomposition – which means without air. For example, when plant matter decomposes under a wet swamp – it produces methane. The same can happen under permanently frozen ground, permafrost. Wetlands are the largest source of natural methane, about 76% of Nature’s production of the gas comes from them. Tropical wetlands are a key factor.
Recent research from the Max Planck Institute in Germany has shown that plants also produce some methane during photosynthesis. So forests and grasslands make some methane, but that greenhouse gas is thought to be less than the total carbon dioxide warming potential consumed by plants, leaving forests as greenhouse gas reducers, or sinks. More science remains to be done on this balance.
The oceans, lakes, and soils also emit some methane. Termites, and some ruminating animals, such as cows, produce methane. There is another worrying collection of methane gas trapped in ice on the ocean floor. This is called methyl hydrate. If the oceans warm too much, this methane-laden slush could melt, releasing bubbles of global warming gases to the surface. There is some evidence this is already happening.
Climate change may also release more methane, by heating up the permafrost in Siberia and Northern Canada. Recent research shows five times more methane coming from Siberia than previously thought.
But more than half of all methane rising into the atmosphere comes from human-related activities. The 2001 report of the Intergovernmental Panel on Climate Change, the IPCC, estimated that 60% of methane comes from our agriculture, industry, and waste. Humans are the biggest single source of methane.
In North America and Europe, the largest single source of methane comes from landfills, where our consumer waste decomposes under soil, without enough air. All our packaging, food waste, and industrial waste produces more global warming gases. If we reduce waste, we reduce climate change. In 2002, the United States EPA calculates that American landfills produced methane equavalent to 131 million metric tonnes of CO2.
Cattle, sheep produce methane in their stomachs as they digest plant material. Despite jokes about “farts” – these animals release methane through their noses. The EPA figured 114 million metric tonnes of CO2 equivalent came from methane produced by agricultural animals. But animal manure, especially from pigs, also produces prodigious amounts of methane, namely 39 million metric tonnes equivalent of CO2. If we add these two figures, American factory farms for meat production were responsible for 153 million metric tonnes equivalent of CO2 – more than landfills, and the largest single source of methane in the United States. Vegetarians argue a simple change of diet could stop the largest source of methane greenhouse gas, and we’ll get to that argument in a separate program, called “The Methane Fix”.
Human excrement also creates a lot of methane in wastewater treatment plants. Petroleum systems, especially leaky natural gas lines, add more methane to the atmosphere. Other lesser sources in the United States were rice cultivation, (where plant material rots underwater, just like in swamps,) and old coal mines.
The world-wide picture is a bit different – and with climate change, global emissions are what count. First of all, unlike carbon dioxide, the United States is not the biggest source of methane as a greenhouse gas. According to the U.S. Department of State, the largest emitters, in order of importance, are China, Russia (along with its former Republics), India – then the United States, followed by Brazil. These countries account for about half of all the human induced – or anthropogenic – methane released into the atmosphere.
In China, the biggest methane source, less comes from consumer waste, and most comes from rice paddies and coal mines. The largest human-made methane source in the number two country, Russia, comes from inefficient natural gas and oil systems. India’s main methane contributions come from rice and livestock.
Some calculate that the industrialized world is responsible for about 20% of human-induced methane, and developing countries 80%.
So tackling methane emissions requires different strategies in different parts of the world. Note that fossil fuels and animal husbandry are methane problems all over the world. But we have to remember, this is not a smoke-stack problem which can be regulated by changes in big industry. Most of our sources of methane come from a wide-variety of normal human activities in the modern world. Even vegetarians eating rice are connected to methane from rice paddies. There is still disagreement about just how much methane comes from rice production, and we don’t have firm figures.
WHERE DOES IT GO?
Methane is removed from the lower atmosphere (called the “troposphere”) by a chemical process. It reacts with a rare and unstable combination of a single oxygen atom and a single hydrogen atom, called a “hydroxyl radical.” That’s a term worth learning, because our future climate may partly depend upon having enough hydroxyl radicals. Many of us have learned about “anti-oxidants” to preserve our health, we need to know about hydroxyl radicals to preserve the planet’s health.
Some methane is also lost to oxidation in soil, but this is minor compared to chemical reactions occurring in the atmosphere. Some methane eventually escapes upward into the stratosphere.
Just how long methane can last in the atmosphere before it is zapped by hydroxyl radicals is still debated. Some sources say less than ten years, while others say up to 15 years. It is also possible that global warming may change the processes that remove methane, increasing its lifetime in the atmosphere.
In any case, methane doesn’t last anywhere near as long as carbon dioxide, which, once created, can stay in the atmosphere 100 years or more. Methane is a much more powerful greenhouse gas, but it doesn’t last as long.
For reasons not yet understood, the level of methane in the atmosphere appears to have stabilized (at the much higher levels) since the 1990s. A study in 2003 by Dlugokencky reveals a steady level of methane between 1999 and 2002 at 1751 parts per billion by volume (ppbv).
Unlike CO2, the American government has taken steps to reduce methane emissions below 1990 levels, but this could not account for the current methane plateau in the atmosphere – given larger inputs from China, Russia, and India.
It is possible that drying of tropical wetlands, including the Brazilian Amazon, likely from climate change, may have offset the new methane coming from increased industrialization and agriculture, and even the warming in the Arctic. We don’t know.
That is the scary part. We think human-induced methane emissions are rising around the world, despite some claimed reductions in a few industrialized countries. The latest science also points to new sources of natural methane, in large volumes, ready to be released by the melting Arctic tundra, and frozen methane from the bed of a warming sea. And we have no idea what is holding back this new wave of global warming gases for the past couple of years.
Scientists worry that world temperatures could jump rather suddenly, possibly within a few years, if the mysterious methane barrier is broken. The Americans, and their partners in the industrialized world, have a plan to control methane and some other trace greenhouse gases in their own countries. Some major scientists, including NASA’s James Hansen, have backed a methane control plan as a way to stave off the worst of climate change.
That is “the methane fix” – the subject of our next broadcast. Find it at www.ecoshock.org under “climate” in the Audio on Demand menu.
Or just look at the previous article in this blog.