Does Global Warming Cause Hurricanes?

No. That’s the short answer. No one factor causes hurricanes, cyclones or tornadoes. However, global warming, (especially the warming of ocean surface temperature) could contribute to an increase the frequency and intensity of hurricanes. Recent studies suggest that hurricane intensities (say more category 4 or 5 storms) may have increased. One scientist, Kerry Emanuel, published a report in Nature predicting that hurricane intensity should increase as global mean temperatures increase. Another report suggests that hurricanes will increase in intensity later in this century.

However, 2005 was one of the worst hurricane seasons ever (we ran out of names on the A-Z list, and had to go to Greek letters, alpha, beta, etc.) with 27 (that’s twenty-seven) hurricanes. And some very surprising things happened. Katrina moved across Florida as a Category 1-2 storm, causing great damage, and then once it entered the warm waters of the Gulf of Mexico, and raged into a Category 5 storm, and hit New Orleans as a very strong Category 4 storm, resulting in the destruction of levees, the flooding of a great part of the city, and eventual evacuation of more than 500,000 people.

A new hurricane season has arrived. The first tropical depression (Tropical Depression 1—it will become Alberto if its winds reach hurricane intensity). The depression formed west of Cuba, and could enter the Gulf and sweep across Florida and South Georgia.

I asked if global warming caused hurricanes. The answer is still no. But, global warming is viewed as contributing the increased intensity of hurricanes. Meterologists predict an active hurricane season. Could this be the result of global warming? I think the answer is probably yes.

It’s Getting Hotter in Atlanta

Well, hot temperatures are arriving in the Atlanta area; but its been hot in Texas. What’s the fuss. It’s summer. Well last year, 2005, was the hottest year during a period of temperature measurements from 1860 to today. These measurements include combined annual land, air and sea surface temperatures. Take a look at the graph below.


High temperature records were set in Reno, Nevada (10 days >100 degrees F; Las Vegas, one day >117 degrees F; Tucson, AZ (39 days)>100 degrees F, and list goes on in the U.S. and around the world.

One of the issues that makes statements of global warming controversial is that people simply say that these high temperatures are just part of a larger cycle, where temperatures go up, and go down. That’s true. But when we look at the big picture with data, we see that the trend, since we started putting lots of greenhouse gases into the atmosphere (around the beginning of the industrial revolution), temperatures around the world began to take off and rise.

There are several projects that have helped students learn how to monitor the environment and share data with students in other parts of the world. Historically, the Global Lab, the Global Thinking Project, and EnviroNet have done this. Currently, The Globe Program involves thousands of schools around the world in collecting data, not only on temperature, but many other variables as well including cloud cover, water vapor, air pressure, relative humidity, precipitation. The project also involves students in hydrology, soil and land cover/biology. In my experience working with middle and secondary school students with their teachers, especially in the U.S., Russia, and Spain, their dedication and involvement in collaborative environmental projects was amazing. They took the work they were doing seriously, and felt as if they were involved in important work. It’s that same level of dedication, and involvement that is needed to deal seriously with global warming.

Measuring CO2 in the Atmosphere

In 1958, Roger Revelle and Charles David Keeling developed with funding the Mauna Loa research station for measuring CO2 in the atmosphere. Samples are collected every hour from 5 towers standing above the volcano. According to their website, “Air samples at Mauna Loa are collected continuously from air intakes at the top of four 7-m towers and one 27-m tower. Four air samples are collected each hour for the purpose of determining the CO2 concentration. The Mauna Loa record shows a 19.4% increase in the mean annual concentration, from 315.98 parts per million by volume (ppmv) of dry air in 1959 to 377.38 ppmv in 2004. The 1997-1998 increase in the annual growth rate of 2.87 ppmv represets the largest single yearly jump since the Mauna Loa record began in 1958.

The graph below shows the relationship between CO2 concentrations in the atmosphere and temperature since 400,000 years ago as measured from samples from the Vostok ice core. Notice that the temperature and CO2 concentrations show a direct relationship. Also notice that the highest range of CO2 is NOT above 300 ppmv.

Now, what do you suppose the temperature graph looks like given the Mauna Loa CO2 results between 1958 – 2006?

An Inconvenient Truth

I’ve been thinking about writing something about Al Gore’s new book, An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do About It.A book such as this naturally controversial, but from at least two points of view. Firstly, its a scientific book written by a “recovering” politician (a term Gore used to describe himself). The controvery is not whether politicians understand science, but whether they let their experience as a politician jade their views, and jump to conclusions. At this point, I haven’t studied Gore’s book is evaluate this point, but my experience with Gore’s previous book was positive, and a careful glance at this new book is encouraging. Secondly, the topic of global warming is controversial, simply by itself. In fact, politics seems to influence the public perception of efficacy of global warming, not the scientific facts that surround and give meaning to global warming. Because Gore’s book has in its subtitle “what can we do about it” it suggests social action, and that by its nature has to involve politics. So my prediction is that this is a book that weaves science and politics, and will give us an opportunity to do something about the warming of earth.

For many years I worked with teachers, scientists, and teenagers on global environmental problems throught the Global Thinking Project. In that project we involved teenagers in carrying out collaborative research projects in which they looked at various environmental problems such as ground-level ozone, global warming, solid waste, and other issues. As Gore points out, the deliberate collection of data over a long period of time (of say temperature, or CO2 in the atmosphere) is important in establishing base levels, and then subsequent changes that occur in these environmental conditions. Making use of core samples(from ice) enables us to compare present environmental changes with changes in the past. One finding in making measurements of say CO2 for past 40 years is that when compared with CO2 in the atmosphere say 650,000 we find that present levels are “way ahead of anything back then.”

Helping people understand how measurements are made, and then looking at trends in the data—as we did with teenages in more than 15 countries—enables citizens to make decisions based on logical thinking.

Gore’s book reminds me of books designed and written by Bob Samples, an educator who has impacted science education, especially during the 60s and 70s. An Inconvenient Truth is a welcome piece of work that would be a powerful tool for science educators and politicians alike.

Global Warning

Global Warning? Global Warming? Which is it? Well, probably both if you take the position of Al Gore, and many climate change scientists. As you know, Gore put together a slide show on the danger posed by the warming of Planet Earth, and then was approached by film producers to use the slide show as a basis for full length film, (An Inconvenient Truth) which was presented at the Cannes Film Festival. Gore then went on to the Hay Literature Festival (a town in Wales) to discuss not only his film, but the book that accompanies the film. Although Gore is a politician, he is as well qualified as many scientists in his understanding of climate change. Some years ago he wrote the book, Earth in the Balance: Ecology and the Human Spirit.

Temperature Rising, an article in this week’s U.S. News & World Report, points out that we may have to live with feeling a bit warmer. There are many consequences of an increasingly warmer planet earth. Melting glaciers, polar caps and ice result in a rise of sea level. Increasing warmth of the ocean results in increasing frequency and intensity of storms such as hurricanes. In the U.S., as in any region of the world, the effects of global warming will vary. For example, in the Southeast, where I live, low lying areas will be more vulnerable to hurricances, sea level rise, storm surges and the intrusion of salt water into wetlands. On the other hand, Alaska is experiencing increased thawing of permafrost. In the northeast, milder winters could continue along with greater precipitation and increased flooding—New England has seen some of most severe floods in the past year.

So what should be done? Some countries and companies are already becoming more efficient when comes to using energy—the chief culprit causing an increase in greenhouse gases, especially carbon dioxide. The major decision about controlling emissions into the atmosphere was proposed via the Kyoto Protocol. The U.S. has not ratified the protocol, although 163 states and regional economic integration organizations have deposited instruments of ratifications, accessions, approvals or acceptances.