Climate Change Casualties

The evidence keeps getting stronger that climate change brought about by global warming is likely to cause disruptions in food production and mass migrations of some people from their homes and homelands within the next century. The latest article, in the January issue of Scientific American, describes three critical “hot spots” to watch – Mozambique, already experiencing more frequent droughts and floods; the Mekong Delta region of Vietnam, a rich farming area that is likely to face severe floods and loss of food production as the sea level rises; and Mexico and Central America, likely to be hit with increased numbers of tropical storms and crippling droughts.

Do we have the will to do something about climate change? Frankly, I’m not sure we do – the problem of global warming is still seen by many nations as either not severe enough, slow to develop, or not their fault (or at least not sufficiently their fault). Most nations have other more urgent issues to worry about first.

My prediction is that nations will spend more money over the next century dealing with the disastrous effects of climate change than they will in joining together to prevent the problems from ever happening in the first place. I sincerely hope I’m wrong.

But then, I won’t be here to see it, will I?

Global Warming Tipping Points?

One of the hottest controversies among global-warming watchers these days is whether or not global warming will ever pass a “tipping point”, setting off rapid, unstoppable, and catastrophic climate change. Do climate tipping points even exist? Or will climate change just continue slowly and inexorably for hundreds or perhaps even thousands of years?

No one knows for sure. But well-meaning climate scientists who believe in tipping points warn of doomsday scenarios in an effort to get people to do something about global warming before it is too late. You’ve heard it all before - the Amazon rainforest will become grasslands; the polar ice caps will melt; the seas will rise several meters, flooding most of Earth’s populated areas; ecosystems will be disrupted. Some climate scientists worry that talk of tipping points could backfire. If a tipping point doesn’t happen within the next couple of decades, will people quit worrying about global warming altogether and decide it’s not worth doing anything about? Yawn! I’m bored with this whole subject…….

The best climate models can’t tell us yet whether or not there are tipping points. And therein lies the danger - there may actually be tipping points. Perhaps more likely is that lots of little tipping points in Earth’s complex climate system will add up to acceleration of global warming the higher the temperatures get.

For a recent news article on the subject, see “Among Climate Scientists, a Dispute Over ‘Tipping Points’”, The New York Times, Mar. 29, 2009.

Earth's Dwindling Arctic Sea Ice

A news article in Science last week (Science Mar. 27, p. 1655) suggests that polar ice may disappear entirely from the Arctic Ocean during the summer in less than 30 years. According to the article, scientists narrowed 23 different climate models down to the six that best fit the data for the ups and downs of sea ice from winter to summer in the past. They then used the models to predict when the summer ice would disappear completely from the Arctic Ocean. The best estimate is somewhere around 2037.

You may live to see polar bears become nearly extinct in the wild. On the bright side (if there is one), marine shipping could occur between the Atlantic and Pacific Oceans through the Arctic Ocean during the summer months.

More on Sequestering Carbon

A good article on current and future methods of carbon sequestration for reducing greenhouse gases is “Down with Carbon” (Science News May 10, 2008, pp. 18-23.) The article is written at a level that students will understand. Some promising possibilities for long-term storage include the bottom of the ocean, in sandstone/saline aquifers deep underground, or in volcanic rock formations. There are also some interesting synthetic materials called zeolites in development that can soak up carbon.

Instructors will be interested in the detailed report by the Intergovernmental Panel on Climate Change (IPCC) entitled “Carbon Dioxide Capture and Storage – Summary for Policymakers”. The article has some great illustrations that would be useful in teaching. They can be used free with acknowledgment.

Carbon Sequestration

A currently feasible technology for sequestering carbon so that it can't contribute to global warming is to store it deep underground. Take a look at the procedure used at Statoil of Norway’s Sleipner West gas field. Statoil is storing 2,800 tons of CO2 deep underground every day, in what is currently the largest carbon sequestration project in the world. Their website has a nice animation that shows the chemical process for separating the CO2 from natural gas, as well as a good reference article that your students could read and understand. We talk about carbon sequestration in the upcoming 5th edition of Human Biology, in the Current Issue on global warming (pp. 556-557).

Strong Hurricanes Get Stronger

This week marks the peak of the hurricane season for 2008. And a new study just published in Nature shows that the strongest hurricanes are getting stronger. The strongest storms now have peak wind speeds that average 16 miles/hour faster than back in 1981 (see “The increasing intensity of the strongest tropical cyclones.” Nature Sept. 4, 2008, pp. 92-95.) The article is not suitable for students, however, unless they have a strong background in statistics.

Over the same time period (1981-2006), the sea surface temperatures have risen by 0.5 degrees Fahrenheit. Most climatologists believe that warmer waters are certain to lead to stronger storms, because hurricanes derive their energy from the heat of warm surface waters.

Global Warming and U.S. Precipitation

A new government report predicts that in the next 50 years there will be significant shifts in precipitation across the United States as a result of increased carbon dioxide in the atmosphere. The report predicts that the arid Southwest and West, already struggling with chronic water shortages, will become even drier. In contrast, parts of the Northeast and East will experience up to 20% more precipitation, leading to increased runoff in streams and rivers. These changes are likely to disrupt water supplies, affect agricultural and forest productivity, and alter ecosystems.

So it’s not just a rising average temperature that we have to worry about with global warming; shifting weather patterns are likely to be just as disruptive. See “Synthesis and Assessment Product 4.3 (SAP 4.3): The Effects of Climate Change on Agriculture, Land Resources, Water Resources, and Biodiversity in the United States”, at climatescience.gov.

Atmospheric CO2 Continues to Rise

The National Oceanic and Atmospheric Administration reported this week that the atmospheric levels of heat-trapping CO2 continue to rise, reaching nearly 385 parts per million in 2007. They blame the continued burning of fossil fuels such as coal, oil and gas. Levels of methane also rose, after a decade of relative stability.

If you wish to update the graph on p. 556 of Johnson's Human Biology, 5th ed., place a green dot at 385 ppmv for 2007 and then re-draw the green line from 2000 to 2007. The line is still curving upward, and getting steeper.

Global Warming and Science Literacy

If people really understood global warming they’d be more concerned about it, right? Wrong! According to a recent survey, respondents who are more informed about global warming and who have a high confidence in scientists “feel less responsible for global warming, and also show less concern for global warming” (Personal Efficacy, the Information Environment, and Attitudes Toward Global Warming and Climate Change in the United States. Risk Analysis 28:113-1267, 2008).

Why is that? The authors suggest that its because “Global warming is an extreme collective action dilemma, with the actions of one person having a negligible effect in the aggregate.” They suggest that because informed persons understand this, they tend to feel less personally responsible and more pessimistic about their ability as individuals to change the outcome.

Okay, informed persons may feel less responsible, but why are they less concerned? One possible explanation is that people who are informed about science tend to trust that scientists will find a technological solution. After all, we’ve sent men to the moon, discovered antibiotics, and developed computers, haven’t we?

How confident are your students that scientists will find technological solutions to global warming in their lifetimes? Do they see any technological solutions on the horizon?

Global Warming and Loss of Species

Many scientists believe that the Earth is losing animal and plant species at a more rapid rate than in past millennia, in part because of the effects of humans on complex ecosystems. For example, human activities such as building cities and highways, clearing and tilling land for food crops, and diverting water resources for our own use all affect the habitats of specific species. But now scientists report that humans may also increase the rate of species extinctions through our effect on carbon dioxide emissions and global warming.

In an article published online in Proceedings of the Royal Society. B, Biological Sciences (doi:10.1098/rspb.2007.1302), British ecologists report that four out of five periods of mass extinctions of species over the last 520 million years coincided with periods of warmer world climate. And according to climate scientists, Earth is now on track to reach similarly warm temperatures within 100 years unless global emissions of carbon dioxide are reduced soon. Fully 20-30% of all species assessed so far “are likely to be at risk of extinction” if temperatures rise just 3-4 degrees Fahrenheit, according to the highly respected and authoritative Intergovernmental Panel on Climate Change (IPCC).

A big issue of the century will be what, if anything, to do about it.

Artic Ice Loss Accelerates

The artic ice cap may be melting much faster than previously thought, according to scientists from the National Oceanic and Atmospheric Administration (NOAA). The scientists tested 20 different climate change computer models for their ability to replicate the sea ice conditions that actually existed between 1979 and 1999. After discarding the models that couldn’t accurately replicate the actual data, they used the remaining models to predict the artic ice melt to 2050. They report that the arctic ice cap may shrink by more than 40% by 2050, even if atmospheric carbon dioxide levels remain where they are today. But it's more likely that carbon dioxide levels will continue to rise, given our appetite for fossil fuels. The original article is published in the September 8 issue of Geophysical Research Letters.

A major loss of arctic ice would be bad news not just for polar bears, but for marine ecosystems in general. The winners: oil and gas companies would be able to explore more of the arctic sea bed for new sources of oil and gas, and ships might be able to use northern shipping routes between the Atlantic and Pacific during the summer months.

Note added Sept. 28: The Oct. 1 issue of Time magazine has a cover story which discusses the political and economic implications of the loss of arctic ice due to global warming. Apparently, nations are rushing to lay claim to the land (and mineral resources) previously under the ice, and shipping companies are eagerly awaiting the time when the Northwest Passage is open, at least for some of the year.