Like many of us, I was thrilled when the 2007 Nobel Peace Prize was awarded to former vice president Al Gore and the Intergovernmental Panel on Climate Change (IPCC). Not only was the award well deserved from a broad international perspective, but it also made me proud that more than 50 NCAR and UCAR staff contributed to the 2007 IPCC report, along with thousands of other volunteer scientists from more than 100 countries around the world. I congratulate all of them!
The scientific verdict is in, and it is loud and clear: Earth is warming faster than at any time in history and human activities are causing most of the warming. Now comes the harder question and debate: what should we as a society and we as individuals do about it? In the previous President's Corner (UCAR Quarterly, Summer 2007), I pointed out the inescapable fact that the growth of human population is the fundamental cause of the present global warming. Here I will comment on some individual behaviors that can help slow global warming while doing other good things, and also point out some pitfalls in some actions that are being widely promulgated as effective.
Despite worldwide attention and concern, emissions of carbon dioxide (the primary human-produced greenhouse gas) continue to soar. Shown here are global emissions of carbon dioxide from fossil-fuel burning, cement manufacture, and gas flaring for the years 1990 through 2004, as reported by the Carbon Dioxide Information Analysis Center (http://cdiac.ornl.gov). All data are in petagrams (billion metric tons) of carbon. Also plotted are the values for 2005 and 2006 (courtesy Gregg Marland, CDIAC). The 2006 value of around
8.4 petagrams represents a 36% increase since 1990 and a 20% increase since 2000.
A first important point to remember is that there is virtually no chance we will reverse the climate change that is already "programmed" for at least the next 30 years. Carbon dioxide emissions increased more than 20% from 2000 to 2006, which is more rapidly than projected in the IPCC's worst-case scenarios—and even large cuts in emissions would start making a real difference only beyond 30 years, according to the IPCC. So, although we are far from knowing the critical regional details of the large changes we are facing in the next generation (which is an important topic of research), these changes will occur pretty much whether we do anything now or not. Thus adaptation must be an important part of societal response.
However, this does not mean that we should do nothing for the next three decades to mitigate the effects of climate change. The changes we make now can have many other benefits immediately and start reducing the rate of climate change that will occur many years from now.
This will not be easy. It is hard to hold people's attention for a sustained period of time when a threat, no matter how great, is not immediate or clear. New York Times writer Andrew Revkin reminded me of the MEGO effect in a talk he gave to the National Research Council on October 17. MEGO stands for "My Eyes Glaze Over" and describes the numbing effect that occurs when people are continually bombarded by facts, information, propaganda, and requests to take various types of actions. It is even worse when a well-organized and well-funded group of contrarians intentionally tries to confuse the public and policymakers by supplying misleading or incorrect information, while denying there is a real problem at all.
One way to fight the MEGO syndrome is to establish good habits that have an effect over the long term and do not require continual conscious rethinking. For example, I have been trained to turn out lights when I leave the room; it is no longer something I even think about. I have also been trained to recycle, so I am uncomfortable throwing away aluminum cans, newspapers, and bottles where there are no recycling facilities.
An increasing number of people are feeling strongly enough about climate change and other forms of environmental degradation that they want to do something more, in addition to reducing their own consumption. This is highly commendable, but it raises another set of issues. What should they do that would be most effective? And how can they be sure that what they do actually makes a positive difference?
Some want to pay for their "carbon sins" by purchasing carbon offsets. In theory this makes up for the "sin" by reducing an equivalent amount of carbon in the atmosphere through some other activity that the buyer funds. The analogy has been made to the practice of indulgences in the Catholic Church in the early 16th century. Wealthy people could buy their way out of the consequences of their sins, or the sins of their relatives in Purgatory, by giving money to the Church.1 Today, wealthy people can buy their way out of their global-warming "sins" by, for example, purchasing carbon offsets for their airplane travel. The idea is to calculate your carbon footprint, reduce the activities that result in carbon emissions (to the extent you can), then purchase carbon offsets for those you can't. You will then be a "carbon neutral" person!
Carbon offsets may appear attractive, but many have argued against them on the basis that they could be misleading, inaccurate, and ineffective, as well as available only to those who can afford them. Offsets have also been criticized as letting rich people off the hook for their actions without doing anything substantive to help solve the problem.
Indulgences aside, people who understand the seriousness of the climate warming problem and want to contribute to its mitigation also have to be careful about scams and taking actions that may have little or no effect, or even a negative effect. History is full of unethical opportunists who take advantage of serious issues to make money from well-meaning but gullible people. The weight-loss industry and the quack remedies offered to cure serious illnesses are cases in point. There are also well-meaning, honest people who offer solutions that they do not fully understand, which may be ineffective or even counterproductive. As the market for solutions to global warming increases, we must strive to support those approaches that are both honest and effective. It may not always be easy to choose. Let me give one example: purchasing carbon offsets from companies who promise to plant trees, which are claimed to fight global warming through the sequestration of carbon.
Before I start this argument, let me assure you I am one of the biggest tree huggers around—I love trees for many reasons, argue against deforestation, etc. But this situation is complex, and trees do not always reduce global warming; in fact, they may contribute to it.
The offer to plant one or more trees that will theoretically sequester enough tons of carbon over the tree's lifetime (say 50 years) that it offsets the offending action sounds good—for $30 I can fly to New York and not contribute to global warming! This approach can be extended to large corporations and even entire nations; for example, the Vatican is aiming to become the world's first carbon-neutral state this year by reforesting 37 acres in Hungary.
However, in order for tree-related carbon offsets to be effective, the following must occur:
- Your purchase of the offset must result in an effective action; i.e., the company must be honest and actually spend your $30 to plant trees that would not have been planted otherwise.
- The company's administrative costs must be subtracted from what is actually used to plant trees, and its energy use and associated emissions must be subtracted from emissions sequestered by the trees.
- The energy and water costs of planting and maintaining the trees over their lifetimes (forest management) must be considered, and the related emissions must be subtracted from those offset by the trees.
- When the tree eventually dies and decays, or is burned by a forest fire, all the carbon it has stored over its lifetime is returned to the atmosphere. Unless the carbon in the tree is stored indefinitely, there is no long-term sequestration.
- And finally, aside from the above, do trees really counter global warming, even when they are alive?
Let's consider the last question, which may seem heretical to some. Many trees, depending on their type and where they are planted, may actually cause Earth to absorb more solar energy than would occur without the trees, and thus ultimately increase global warming. This is because a tree's albedo (reflectivity) is very low, among the lowest of all land features. The albedo of a typical tree is around 10%, meaning it absorbs about 90% of the visible portion of the Sun's spectrum, the most energetic part. Bare soil or sand typically have an albedo of 20–40%, which means trees absorb 10–30% more solar energy in the visible part of the spectrum compared to unvegetated land. Snow cover has an albedo as high as 80%–90%, and trees typically lose their coatings of snow quickly as the accumulation slides or blows off. Therefore, forests in the winter may absorb as much as eight times as much visible solar energy as do unbroken fields of snow. Even in summer, you can see this albedo difference in photographs from space or aircraft of regions that contain forested and unforested areas (see photo).
This photo of a volcanic field in the Pinacate area of Mexico, just southeast of Yuma, Arizona, shows the sharp contrast in albedo between forested/vegetated regions (the dark areas at right) and bare soil and sand (the lighter areas at left). (Image courtesy of Earth Sciences and Image Analysis Laboratory, NASA Johnson Space Center.)
When you consider the energy put into planting and managing forests, the extra energy absorbed by the forest over its lifetime, and the return of the stored carbon when the trees die and decay or are burned, it is not hard to see how in the long term planting trees is no panacea to global warming. A number of scientific studies (e.g. Bala et al., 2007) have considered the effect of trees on climate. They show that in general, trees in middle and high latitudes contribute to global warming, while trees in the tropics have a net cooling effect. This doesn't mean we should tear down temperate and high-latitude forests to reduce global warming. As Ken Caldeira (Carnegie Institution) wrote in a New York Times column earlier this year, "Clear-cutting mountains to slow climate change is, of course, nuts." ("When Being Green Raises the Heat," 16 January 2007). Still, the bottom line is that, for the planet as a whole, trees really do contribute to global warming.
If trees aren't the best type of carbon offset, what else can you do as an individual? Some forms of offsetting appear to provide real benefits, provided they are chosen carefully. One good source of information is the Tufts Climate Initiative, which has ranked offsetting firms on a number of objective criteria. Its Web site includes offsetting guides for both consumers and organizations.
Tufts University is one of the nation's leaders among academic institutions working to reduce their carbon footprints. More than 400 have signed on to the American College and University Presidents Climate Commitment, including more than a dozen UCAR members and affiliates. These institutions have pledged to move toward climate neutrality through a blend of offsets, energy efficiency, renewable energy sources, and waste reduction; the exact mix varies with each institution. At UCAR, we are in the process of hiring our first environmental coordinator, who will help us examine our own carbon footprint and recommend steps to reduce it. I took a look at UCAR's energy use and efforts at conservation a couple of years ago in the Winter 2005-2006 issue of UCAR Quarterly.
Even as institutions work to address climate change, individuals can accomplish a great deal as well. My suggestion is to do things that have an immediate, efficient, and demonstrable impact and have other beneficial effects as well, such as lowering our dependence on limited domestic and foreign energy supplies, reducing air pollution, and saving money. A few, such as walking and cycling instead of driving, also are good for your health. Some proven examples that are nearly 100% efficient and effective:
- Replace your automobile with a more fuel-efficient one.
- Where possible, take the bus or train instead of driving.
- Improve insulation in your house or business.
- Turn off lights, appliances, and computers when not in use.
- Lower thermostats in winter and raise them in summer.
- Wear sweaters in winter and use fans rather than air conditioners in summer.
- Replace regular incandescent bulbs with compact fluorescent bulbs; they last up to ten times longer, use about one fourth the energy, and save you money in the long run.
1In northern Germany a Dominican friar, Johann Tetzel, was credited with hawking indulgences for the dead by saying, "When a penny in the coffer rings, / A soul from Purgatory springs."