A series of guest blog entries by Dr. Kevin Czakjowski on the 2008 Surface Temperature Field Campaign will be interleaved with the regular Chief Scientist blogs. See the Introduction to the Surface Temperature Field Campaign.

I’ve often written about clouds on this blog. They are so easy to observe. Today I’m writing about birds since they are easy to observe as well.

It’s fun to watch birds. Many people spend their lives counting how many birds they have seen over their lifetime. I started doing this recently as well. But I find the more interesting part of my “life list” tends to be notes about what the birds are doing. For example, “We saw a half-dozen Yellow-Headed Blackbirds foraging on a lawn in the middle of a blizzard,” or “The fledgling Kestrels were learning how to fly under the watchful eye of both parents,” or, “At sunrise, we watched the Crows fly from the foothills to the west into town for a day of feeding.”

Although a pair of binoculars helps in watching those birds that are small or far away, you can see an amazing amount close up. This is particularly so for tamer ducks or geese. In the United States, we often see Mallards or Canada Geese (Figure 1). And many are not too afraid of people, so you can watch them without disturbing them too much.

Figure 1. Male Mallards (right) swimming with a Canada Goose. Little Dixie Lake, Boone County, Missouri, U.S.A.

Mallards have an interesting way of feeding. Their front ends go under water and their back ends tip into the air. This is called “dabbling” (Figure 2). Mallards eat mostly plants – grains, seeds of some trees, bulrushes; but they also eat some animal matter as well, such as mollusks, insects, tadpoles, snails, and so on.

Figure 2. Dabbling Mallards. Also at Little Dixie Lake

Unlike watching clouds, you can “watch birds” without looking at them. When I was a teenager, I went birding with a blind man on the island of Oahu in Hawaii. He could tell what birds were around simply by their calls – and maybe a little bit from the noise the birds make as they move around, since some species sit in one place, and others flit around. He would describe to me what the bird looked like and point in the direction the sound came from. I met another birder who often observed birds from their sound. He starting doing this because he was a runner, and he didn’t want to have to stop and look. And knowing the bird sounds is useful when you simply can’t locate a bird hiding in a tree or bush. And you don’t need binoculars.

It’s important to stay far away from wild birds or their nests. During nesting seasons, many parks and nature reserves close nesting areas so that the birds can raise their young undisturbed. Also, you shouldn’t feed the birds in wild places. If you want to watch wild birds, you should keep your distance and use binoculars. Or watch them from a blind, or if you are lucky enough, through the window of your home or school.

Birds and the Seasons

The migration of birds in the spring and fall has thrilled people for centuries. In North America, we like to hear the honking of geese flying overhead during the spring and fall. The Canada Geese fly in large V-formations. This enables the geese to the rear to benefit from the air currents created by the geese in front. If you watch closely, you will see them change places once in a while.

Although you can enjoy birds any time of year, the best times to watch birds is in the spring, when the males are singing to attract mates. Each species has a different song, and the songs can vary from place to place. Or even, though less so, from bird to bird. At this time, it’s even more important to keep your distance and use binoculars to watch them.

Why do birds migrate? No one knows for sure, but it probably has to do with finding food and a safe place to make a nest. And this will vary, like migrations, with the type of bird. In the far north, for example, there are fewer predators that could survive through the harsh winters, so nesting there might be a bit safer for birds that nest on the ground during the summers. Insect-eating birds won’t want to spend much time in an area when the temperature is too cold for insects.

One interesting topic that scientists are studying now is how climate change affects bird populations. Many scientists have found that birds arrive earlier in the spring than they used to. Also, some birds are extending their ranges northward. In the GLOBE Seasons and Biomes/IPY Pole-to-Pole video conference (see March 2007 blog), one of the teachers noted that Magpies were reaching farther northward into Alaska, for example. Scientists continue to try to sort out the role of climate change in the changes of numbers of different types of birds. There are many other factors to consider, such as the number and type of predators, changes in land use, and the use of pesticides.

What birds are you seeing this season? Ask older members of your family if the types of birds are different now, or if their numbers have changed.

And, if you are interested in further information about observing hummingbirds, go to This Week at Hilton Pond.

I’m going to write a little bit more about a “climate misconception” to follow up on the blog I did a few weeks ago. This relates to how our cutting back on carbon production affects the amount of carbon dioxide in the atmosphere. In the earlier blog, I stressed the long lifetime that carbon dioxide has in the atmosphere as being an important reason why it will take a long time to reduce the amount of carbon dioxide in our atmosphere.

But I missed an important misconception: many think that simply keeping the amount of carbon dioxide we release the same will keep the carbon dioxide in the atmosphere the same. Similarly, many think that reducing the amount of carbon dioxide we release will reduce the amount of carbon dioxide in the atmosphere.

As recently discussed in a recent article in Science, there is a fundamental misconception. We forget that the total amount of carbon dioxide in the atmosphere relates to how much we release and how much nature (or, if you prefer, the Earth system) can absorb.

The article describes a question asked of students at the Massachusetts Institute of Technology – a very smart bunch of people. The question went something like this:

Suppose we put twice as much carbon dioxide into the atmosphere as the earth system can absorb. How will the carbon dioxide in the atmosphere change if we keep producing the same amount of carbon dioxide?

A surprisingly large number thought that the carbon dioxide in the atmosphere would stay the same if we didn’t change our habits at all.

Does that seem right to you? Perhaps it does, because we have seen reports of increased amounts of carbon dioxide put into the atmosphere by humans, and an increase of carbon dioxide in the atmosphere. So we might be led to think that if we keep putting in the same amount of carbon dioxide, then the amount of carbon dioxide in the air will stay the same. And we can reduce the amount of carbon dioxide in the air simply by reducing the amount we put into the air.

But let’s stop and think a minute. The question states that the earth system can absorb just half of what we are putting in.

Suppose we have a bathtub. We turn on the water faucet full blast and leave the drain open, so that the amount of water going into the bathtub is twice what is draining out.

Do you think that the level of water in the bathtub will remain the same? Or are you worried that the bathtub will overflow?

Let’s go through the bathtub problem step by step.

Start with an empty bathtub.

In one minute –10 liters of water comes out of the faucet, and we drain out five. (At least this is what happened when I did it.)

At the end of one minute, how much water is in the bathtub – five liters!

Figure 1. Putting water in a bathtub (well, a funny-looking bathtub) and draining it out.

And the end of the second minute, another 10 liters of water has come out of the faucet, and five have drained out.

How much water is in the bathtub? Five liters, plus the ten liters from the faucet, minus five liters that drained out – that’s 10 liters.

Figure 2. Filling up the same bathtub, after two and three minutes.

At the end of the third minute, another 10 liters of water has come out of the faucet, and five have drained out. How much water is in the bathtub now? Ten liters already there, plus the ten liters from the faucet, minus five liters that drained out … 15 liters!

I could continue on, but I think you have the idea – the bathtub is filling at the rate of 5 liters a minute.

Now let’s go back to the carbon dioxide? What do you think now? If you think that the amount of carbon dioxide in the atmosphere will increase with time, even if we release the same amount into the atmosphere, you have the right answer!

Of course, our atmosphere (and people) are much more complicated than that. Different parts of the earth system – trees, grasses, the ocean – take carbon dioxide out of the atmosphere in different ways. And there could be other natural sources of carbon dioxide. We have a good idea about how things work, and what possibilities there are, but there is still much we don’t know. Thinking about the bathtub again, the drain might clog up a little bit or drain better, or water could be flowing from a second faucet.

This blog was inspired by the Policy Forum, by John D. Sterman in the 24 October 2008 issue of Science.

Understanding something as complicated as climate change is really tough. So it’s easy to understand why people don’t always get things right. But it’s much easier to explain why the term “global warming” is misleading than it is to explain why some climate-change messages are only partially understood. So I put the “partial misconceptions” in a separate blog.

Partial Misconception: The greenhouse warming is due to carbon dioxide. Figure 4 shows that slightly over half of the warming near Earth’s surface is caused by carbon dioxide (CO2), with other gases – methane (CH4), Nitric oxide (N2O), halocarbons, and ozone in the lower atmosphere, accounting for the rest of the “forcing.” What is forcing? Forcing can be thought of as a “push” that warms (or cools) the Earth system.

The warming that results is actually larger then you might expect from an increase in these gases alone. This is because the warming surface and air leads to more water vapor, which is also a greenhouse gas. This leads us to the next partial misconception.

Figure 4. Effect of greenhouse gases and aerosols on surface air temperature warming, in terms of “forcings.” From 2007 report, Intergovernmental Panel on Climate Change.

Misconception: Carbon dioxide is the most important greenhouse gas. Certainly this is what you might expect from a first glance of Figure 4. But where is water vapor? I was taught as an Atmospheric Science graduate student that water vapor was the primary greenhouse gas, but carbon dioxide was also important. Modeling studies with various degrees of simplification confirm this first impression. A nice summary can be found on the RealClimate blog.

Why, then, do so many people say that carbon dioxide is the “most important greenhouse gas.” It’s probably because of figures like Figure 4. Note a very important adjective at the bottom which is often ignored, “anthropogenic,” meaning “made by humans.” Humans of course affect water vapor as well, but it cycles through very fast, and the amount of water vapor in the air is basically controlled by the temperature of the air and surface. In a climate model, water vapor continuously adjusts to the conditions within the model, while anthropogenic greenhouse gases in Figure 4 are adjusted by those who run the model.

Put another way, water vapor doesn’t appear in the “forcing” terms for climate models, because it is “internal” to the system. It changes as the result of a “feedback” within the model. Thus external inputs like solar radiation, changes in ground cover, and gases introduced into the atmosphere by human activity are counted as “forcing” but water vapor as not.

In short, we can say that carbon dioxide is the most important greenhouse gas whose amount people are directly altering. Not just in models, but in real life.

Partial Misconception: The warming climate means more exposure to dangerous diseases. I say “partial misconception” because there are multiple factors that change our exposure to disease. Many articles in scientific journals and newspapers discuss increased exposure to malaria, for example, in a warming climate. But that is not the whole story. For example, in the United States, malaria was a real threat over much of the country in the 1700s and the 1800s, and even into the early 20th century. However, public health efforts such as mosquito control and changes in peoples’ habits (for example, using window screens to keep out mosquitoes or staying indoors from dusk to dawn) have largely removed the malaria threat. Similarly, world travel spreads germs, such as the West Nile virus, around the world. This is not a new phenomenon. Europeans coming to the Americas brought small pox with them, leading to the tragic death of countless Native Americans. And populations moving into new areas can expose themselves to new germs.

However, we cannot ignore the fact that vectors for existing diseases will migrate with their preferred climate. Thus at some time in the future, some diseases will show up in areas where they haven’t been before; and in other areas where they have been suppressed.

Partial misconception: The warming climate means more birds will die. Again, there are many factors involved. There are stories of bird populations suffering because food supplies (for example caterpillars) are no longer available when the birds need them, because the two species are responding differently to climate change. However, songbird populations have also suffered because the scarcity of predators like wolves has led to an increase in the number of animals (like raccoons) who eat birds’ eggs. Similarly, pesticides have done serious harm to bird populations. This contributed to a ban on the use of the insecticide DDT in many countries. Finally, the West Nile virus has led to the deaths of many birds (although the magpies and crows, which fell victim to West Nile, seem to be recovering here in Boulder).

Once again, we cannot ignore the impact of climate change. If climate changes continue at the predicted rates, then the entire ecosystem will have to adjust to a new seasonal cycle. This will not be a smooth process: different plants and animals will respond in different ways. And, as in the case of the birds and caterpillars, the food supply will be interrupted at critical times.

Partial Misconception: If we cut back on our production of greenhouse gases, global warming will “go away.” This is true only over a very long period of time. It will take hundreds of years to decrease the carbon dioxide content back to pre-industrial levels through natural processes (the lifetime of carbon dioxide in the atmosphere is around 120 years). This does not mean we shouldn’t consider reducing carbon-dioxide emissions, because continuing the increase in carbon dioxide leads to even more warming than if we slow down the increase in carbon dioxide. One hopeful note is that not all greenhouse gases last as long as carbon dioxide, so reducing their release in the atmosphere might help on shorter time scales. Another hopeful note is that people are studying ways to take carbon dioxide out of the atmosphere, but this is the subject of another blog.

So, when you read or hear about the effects of people on the environment, or try to figure out what you can do to help the environment, please remember that we affect our environments in many ways. Similarly, actions we take to help our environment can improve our environment in many ways. But responding to climate change will remain a challenge for years to come.

As noted in previous blogs, many of us don’t understand the terms people use in describing climate change; nor do we always understand how ideas related to global climate change relate to everyday life. So I decided it would be useful to write about some of these common misconceptions or partial misconceptions. I’ll start with the misconceptions.

Misconception: The term “global warming” means the temperature is getting warmer everywhere. “Global warming” sounds to many (including me) like the temperature should be warming everywhere. If there is “global warming” shouldn’t it be getting warmer where I live? Or, if it’s not getting warmer where I live, how can “global warming” be happening!

If you look at the recent temperature records from several GLOBE schools, the temperature does seem to be warming gradually in some places. But other schools show a cooling trend. It is the same way with the stations used to monitor climate change. As noted in my July 2008 blog, the global average temperature change is often much less than the trends at local sites.

The term “global warming” really means that the yearly average of the temperature averaged over all the Earth’s surface is rising over time scales of several years.

Misconception: We just had a month that was the coldest on record. That means that the climate has started to cool again. When I stop thinking like a scientist, I also briefly think – or hope – that a cold month means that “global warming” will go away. But a record cold day or month doesn’t mean that the climate is getting cooler on the long term.

In a warming climate, there are still changes in both directions from day to day, month to month, and year to year. But there will be fewer record cold months. And there will be more periods of record high temperatures. For example, the city of Chicago in the Midwestern United States is having more heat waves, as illustrated by Figure 1 (taken from the blog, “Regional Climate Change, Part I: Iowa Dew Points and Chicago Heat Waves,” 22 March 2007).

Figure 1. Temperatures during Chicago, Illinois, USA heat waves. While the graph was made to show how the dew point has risen during the heat waves, the increase of the number of points (heat waves) with time shows that there are more heat waves than there used to be. Figure based on data from Changnon et al. (Climate Research, 2003).

Misconception: Earth’s temperature will steadily warm (as in “This year is warmer than last year, and next year will be warmer than this year.”). The globally-averaged yearly temperature record in Figure 2 has many dips and peaks. It is well-known that strong El Nino events, through spreading warm water across the tropical Pacific, will cause peaks in the record (There were strong El Ninos for example in 1982-3 and 1997-8). Similarly, volcanic eruptions can cool the surface temperatures globally for a year or two.

Figure 2. Annual average temperatures, averaged over the Earth. Data from the UK Hadley Centre.

There will be even more extreme year-to-year changes locally. Some regions will have colder-than-normal periods due to persistent airflow from the Polar Regions. At the same time, there will have to be compensating airflow toward the poles in other regions, which will have warmer-than-normal periods. If you look at any local temperature record, such is the one in Figure 3; there are year-to-year changes that are faster than the overall warming trend. Even though there is a general upward trend in temperature as indicated by the straight line, the warmest year on record was 2000. On the other hand, 1998 was the warmest year in Figure 2.

Figure 3. Average annual temperature at the GLOBE School 4. Zakladi Skola in Jicin, Czech Republic. From 15 July 2008 blog.

Misconception: The “warming” scientists write about is not real. Many thermometers are showing warmer temperatures because their surroundings have changed over time, and this affects the global average You can find web sites showing weather stations next to buildings, air-conditioning heat exhausts, and so on. So this is certainly true for some sites. However, climate scientists try very hard to eliminate such sites from the climate record. There are literally thousands of weather stations in the United States today, and a similar density of sites exist in other parts of the developed world. These are used for many things, such as weather forecasting, keeping track of weather at airports or along roads or railroad tracks, or for education and outreach purposes by television stations or schools. But only a small fraction of these are used to document the global change in temperature. It is important to know that the temperature at any station is not taken at face value. Each measurement is checked carefully. For example, each station is compared to nearby stations to see if their temperatures are biased or just plain wrong.

At the GLOBE Learning Expedition, we saw a climate-monitoring station, on a rocky hill at the southern tip of Africa, away from any urban influence (11 August 2008 blog). And, only 30 per cent of the Earth’s surface is covered by land – the other 70% of the area is over the ocean. There, ships, buoys, and now satellites supply the needed measurements.

This does not mean that the warming recorded by sites that were once rural but are now surrounded by cities is not telling us something. Cities are warmer than the surrounding rural areas. They have more concrete and asphalt, which means that more of the incoming solar radiation is converted to heat rather than used in photosynthesis or evaporation. Also, factories, buildings, cars, and even people release energy that warms the environment. If you move from a rural area to a city, you will experience a warmer climate. However, this “urban heat island” has only a small effect on the global average because cities cover only a small fraction of Earth’s surface (See “Land Use: How Important for Climate, 11 June 2008).

Also, we need to remember that the famous surface-temperature curve shown in Figure 2 is not the only evidence that the climate is getting warmer. Satellite data also indicate warming at and near Earth’s surface, as does the shrinking of most glaciers and the smaller extent and thickness of Arctic sea ice (see, e.g., http://svs.gsfc.nasa.gov/goto?3464) . Furthermore, sea level is rising slowly, a result of more water in the ocean basins (from the melting of ice on land) and expansion (as the water gets warmer). And there is more water vapor in the atmosphere than there used to be, consistent with more evaporation (to be expected from water land and sea surface temperatures as well as warmer air).

The amount of CO2 given off by industry in a year

Figure 1 is a diagram of the carbon cycle from the GLOBE Carbon Cycle Project, based at the University of New Hampshire. This diagram shows where the carbon is, and where it is going. So, for example, industry produces about 6 petagrams of carbon a year. What is a petagram? A petagram is written 1,000,000,000,000,000 grams, which can be written 1 times 10^15.

In order to compare the value of CO2 production for human respiration to the “flux” or exchange terms in the diagram (in red), we have to (a) convert it to a flux for carbon rather than CO2 and (b) compute a total for the entire world population for a year.

So, we take

0.9 kg per person per day, times
6,700,000,000 people in the world, times
365 days in a year (neglecting leap years), to get
220,000,000,000 or 2.2 x 10^11 kg or 2.2 x 10^14 grams, or

0.22 petagrams

To convert this to carbon, we multiply by 12/44, the fraction of CO2 that is carbon, to obtain 0.06 petagrams a year.

From Figure 1, that’s about 1% of most of the exchange terms, and about one-hundredth the carbon released by burning fossil fuels globally. And less than one-thousandth the amount of carbon uptake by plants.

What does this really mean? It was pointed out to me by Richard Wolfson, a professor of physics at Middlebury College [who wrote the book Energy, Environment, and Climate (W.W. Norton, 2008), cited a few blogs ago.], that we get our energy from plants, or animals that eat plants, or animals that eat animals that eat plants, so one could argue that we are “carbon-neutral” in the sense that we are part of the natural system, with the plants taking back the carbon we emit. Only in a sense, however – as Wolfson notes, our food production is not carbon-neutral: we produce carbon dioxide in growing the food and transporting the food, not to mention keeping it warm or cold, and, usually, cooking it.

Figure 1. The carbon cycle. The numbers in blue in represent the amount of carbon stored (e.g., 38,000 petagrams of Carbon in the ocean). The numbers in red represent “fluxes” – carbon flowing from one part of the earth system to another. Figure © GLOBE Carbon Cycle.

CO2 from Space

Figure 2 is a snapshot of the global distribution of CO2 at 8 kilometers (5 miles) above the surface. This is high enough so that there is a lot of mixing by the winds, but you can see a pattern anyway. And the pattern is associated with the sources and sinks of carbon in Figure 1.

Figure 2. July 2003 average CO2 from the Atmospheric Infrared Sounder (AIRS) on the Aqua Satellite. From http://www-airs.jpl.nasa.gov/Products/CarbonDioxide/. Preliminary data.

For example, the higher values are associated with the industrial parts of the world. The high values in the north Atlantic are downstream from the United States and Canada. The lowest values are over the high-latitude oceans in the Southern Hemisphere and over Antarctica.

Figure 3. CO2 from AIRS. From http://www-airs.jpl.nasa.gov/Products/CarbonDioxide. Preliminary data. The curve shows carbon dioxide decreasing in the Northern Hemisphere spring and summer, when vegetation is growing and leafing out, and increasing in fall and winter, when respiration dominates.

The “snapshot” in Figure 2 is from the Atmosphere Infrared Sounder (AIRS) on the NASA/Aqua satellite. These data can also be used to look at trends in the global average CO2. Like the well-known surface-based curve from Mauna Loa, there is an upward trend, and you can clearly see the effect of the seasons. If you compare this figure to the curves in the blog Land Use and CO2, posted 7 September 2007, you will find the curves quite similar, with CO2 decreasing during the Northern Hemisphere spring and summer. As noted there, this decrease in carbon dioxide is associated with photosynthesis. During photosynthesis the plants take carbon dioxide out of the atmosphere and use it to grow and leaf out. It is not surprising that photosynthesis is the largest term in Figure 1.