I. Are we prepared for the consequences of global warming?

Last week, NOAA announced its predictions for the 2006 hurricane season, warning of another active season with up to 6 major hurricanes that will attain a Cat 3 or higher status. One of the biggest concerns raised by this report is, “Are we prepared... this time?”

The catastrophic devastation in New Orleans following Hurricane Katrina – its real costs in lives, resources and security – is a reminder that there are tragic consequences for being ill-prepared. Yet, even as our scientists continue to develop and report some of the most accurate climate modeling predictions, it's clear that our government is not responsibly preparing for the consequences of global warming. Our nation may pride itself on its scientific and technological achievements, but this is a global problem -- indiscriminate of national borders.

Next year in January 2007, the IPCC will present its 4th Climate Assessment Report, conclusively detailing its findings from the consensus of the scientific community that global warming by human-caused fossil fuel combustion will lead to a global crisis within this century. Based on the IPCC 2001 Report alone, global warming has been shown to have profound consequences on climate and the global community already. But as we struggle to adapt to and prevent potential adverse environmental and ecological events, the impacts on our social, economic and cultural foundations will certainly be challenging as we face a century that could be hallmarked by human-caused climate crisis.

The impacts from global warming are clearly evident everywhere around the world today. Among the most visible and dramatic impacts are the record losses of land ice due to ice sheet and glacier melting, which, in turn, is leading to a rise in sea level.

-Glaciers are melting at record rates
- Glacier National Park- The USGS (US Geological Survey) has predicted that glaciers at Montana's Glacier National Park will completely melt in the next 40 years. The picture below illustrates the significant rate of glacial ice melt since the start of the industrial age.

- Antarctic Glaciers: A British Antarctic Survey compared aerial photographs from the 1940s with recent satellite photography on Antarctic glaciers. Of the 244 glaciers studied on the Antarctic Peninsula , 87% were shrinking. Furthermore, average air temperatures on the Antarctic Peninsula have risen by about 2^oC in the last 50 years. (http://news.bbc.co.uk/2/hi/science/nature/4471135.stm).

Photographer Gary Bausch provides a photographic archive comparing before and after images of major glaciers around the world.

Another dramatic example of glacial melting became evident after the Chinese Academy of Sciences warned that global warming has caused an average increase of 2^oF over the past 20 years. As a consequence, glaciers on the Tibetan plateau are vanishing at an accelerated rate of 50% every 10 years. This loss is so significant that the volume of water currently melting off is equivalent to the total current volume of water that passes through China's entire Yellow River each year.

- 2005 marked a record year of ice sheet melting in Greenland, surpassing the previous record just 3 years earlier in 2002, based on analysis by Waleed Abdalati at NASA's Goddard Space Flight Center of satellite images (see figure below). Antarctica's ice sheet melting was also occurring rapidly and clearly evident from similar satellite analysis.

During a speech last February at the New School, the Director of NASA's Goddard Space Flight Center, climatologist James Hansen, commented that polar ice sheet and glaciers were melting at an accelerated rate since 2000. Last year, the annual loss of ice in Greenland peaked at 36 cubic square miles of ice. In Antarctica, up to 36 cubic square miles of ice was also lost due to the impact of global warming and melting.

- Interestingly, Dr. Hansen further warned that the rapid ice melt could lead to an “explosively rapid" collapse of Greenland's ice sheet since the properties of meltwater flows can serve as a lubricant, allowing huge segments of ice to slip into the Atlantic.

- During the last 100 years, the earth’s climate has increased by about 1^oC (1.8^oF). As a result, polar ice sheet and glacier melting, together with thermal expansion of ocean water, would contribute to potential sea-level rises of approximately 1 to 2 mm/year. The USGS compiled the table below, indicating that the potential sea-level rise could reach as high as 80 meters should complete melting occur of all the ice masses combined.

- What is perhaps the most serious consequence of potential sea level rise (coastal flooding) is something that could occur to a quite significant degree by the end of this century. As illustrated below, a rise of just 10 meters (~30ft) would result in major coastal flooding along US Gulf and eastern shore communities. And based on statistical data from the 1996 US Census, this level of flooding would impact greater than 25% of all Americans who live within this region.

There is no consensus in the scientific community at this time that global warming is behind the higher than average number of Atlantic hurricanes. For instance, several scientists note that the current increase in the number of hurricanes is to be expected as a part of a known cyclical pattern: the period from the 1920s to the 1960s was also a period with a high number of hurricanes.

But, as for another aspect of hurricane seasons, hurricane intensity, NASA climatologist, Dr James Hansen, recently concluded from his climate model simulations, "which," he wrote, "do a good job of matching observed global climate change,” that the intensification of hurricanes in the Atlantic basin were due to human-caused fossil fuel emissions (“Science and Politics”, The New School, NYC 2/2006).

Dr. Hansen's conclusion is supported by two recent studies that indicate hurricane strength is intensifying:

- In one recent report, Peter Webster of the Georgia Institute of Technology examined satellite records of storms around the tropics over the past 35 years. Although he found no long-term trend in the number of storms, he did find an increase in the number of category 4 and 5 tropical cyclones (hurricanes and typhoons). Globally category 4 and 5 storms climbed 57% from the beginning of the time period to the end.

- In another study, meteorologist Kerry Emanuel of MIT calculated the total power released during the life of Atlantic and western North Pacific storms. The stronger winds and longer storms indicated that the power dissipation index rose between 40% and 50% from the first half of the 45 year record to the second half, which is in step with rising ocean temperatures.

Finally, it's particularly noteworthy that while over the Gulf of Mexico, Hurricane Katrina's sustained winds of 175 mph made it one of the strongest Atlantic hurricanes ever recorded. As such, and with the above studies in mind, Hurricane Katrina's catastrophic impact on the city of New Orleans and on the people of the Gulf states may indeed mark an important new example of the consequences of global warming, especially on some of our more vulnerable coastal structures - natural and man-made.

An issue that generates the most concern for western Europeans is whether or not their region will experience a mini Ice Age (or cooling down) by the shutdown of the "Gulf Stream Global Conveyor Belt". Although this appears highly unlikely, we must first address the question, "What is the 'Gulf Stream Global Conveyor Belt?' Then we can better address the question, "What will happen if this system shuts down?"

Global climate is intricately tied to the global oceanic circulation system, which is driven by a process called thermohaline circulation. It's the basic properties of temperature (thermo) and salinity (haline) in water that essentially drives currents like a conveyor belt. Generally, the mechanics of this circulation are dependent on three processes: tidal forces, wind stress, and density differences. And together, these processes participate in what is mostly a closed loop system of circulation, also referred to as the global thermohaline conveyor belt (or 'Gulf Stream Global Conveyor Belt').

1. The Gulf Stream (and its extension, the North Atlantic Drift) is shown above as part of a larger inter-oceanic current system, connecting the North Atlantic, tropical Atlantic, South Atlantic, Indian and Pacific Oceans.
2. As warm Gulf Stream water and its warm air masses enter the North Atlantic Drift, it conveys warm and salty water to the NE Atlantic.
3. As the water cools, it mixes with the colder (less saline) Arctic Ocean. The water becomes dense and eventually sinks to the south and east of Greenland. (aka "Deep Water Formations," see illustration)
4. Water from these two main sinking regions spreads, displacing water in a continuum that drives the colder sub-surface oceanic currents (in blue) at depths of 1000m and deeper.
5. Gradually, as this cold, dense water warms, it returns to the surface and again flows throughout the world's oceans in an essentially closed loop. (description adapted from Hadley Centre for Climate Prediction and Research, UK)

In order to better understand its impact on global climate, we need to understand the process a little more.

As polar fresh water melts from ice sheets and glaciers, it dilutes the salty water making it less dense, and, consequently, less able to sink. This can slow the flow of the conveyor belt. If less water is coming down from the Arctic, less warm water can come north.

In fact, this appears to be the case. Bryden et al. (Nature 438: 655-657, 2005) recently recorded ocean currents at different depths in the Atlantic Ocean at 25^oN from the bulge on the African Coast to the Bahamas. Based on previous oceanographic measurements recorded during the years 1957, 1981, 1992, 1998, and 2004, they reported a 30% reduction in the warm currents that carry water north from the Gulf Stream. In addition, the warm water that isn’t going toward Europe needs to go somewhere. Indeed, data shows that the subtropical circular flow (gyre) is getting stronger, redistributing warmer water masses back into the tropics, where hurricanes form.

Such changes can potentially have a broad and serious impact on western Europe and the United Kingdom for multiple reasons:

(1) The Gulf Stream primarily provides western Europe its warmer climate (www.TheOilDrum.org, www.RealClimate.org).

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(2) The Gulf Stream circulates and distributes vital organic nutrients, a circulation known as the “biological pump,” to the Atlantic's marine ecosystem.

This is an important point that is often understated. In fact, zooplankton and diatoms dominate the upper strata of the ocean and provide essential nutrients up the food web, but have suffered significant declines in number. In the Atlantic, such a decline imposes potential adverse consequences on coastal fishing industries. Aside from over fishing, disturbances in the speed of the conveyor belt and biological pump could make populations of cod and herring particularly vulnerable, as well as all marine life.

Climate change studies have reported significant ecological pressures as warmer climates shift northward in the northern hemisphere. Many studies have confirmed that shifts in plant growth and feeding behavior of animals have evolved in synchrony. Yet rapid alterations in predator/prey relationships, feeding behavior, population density and migratory patterns present ecological stresses. Warmer climate trends are now known to cause major disturbances in this interdependency, especially as foreign species of plants and animals, adapted to warmer climates, encroach upon territories and habitats that were once occupied by native animal and plant species. Therefore, any imbalance in an already harsh environment will have serious ecological consequences up and down the food chain.

However, the ability of species to survive will depend on their adaptation potential to a warmer or hotter climate and their ability to compete with invasive species or adapt to extinctions of native ones. For example, global warming has resulted in hotter climates in the tropics of South America, which consists of delicate ecosystems that often cannot tolerate even a few degrees of higher temperature.

Mass extinctions of native species could occur as a consequence and are already occurring at an alarming rate. But by 2050, Chris Thomas, a conservation biologist at the University of Leeds in the United Kingdom, warned that global warming could result in mass extinctions of thousands of species, and "doom" millions from a report by 18 scientists in the journal Nature.

-Impact on Coral Reef ecosystems

Coral reefs support the greatest diversity of marine life and are a vital component for its ecosytem. Coral reefs are built by colonies of tiny sea animals, called coral polyps, and by algae. Rising temperatures, however, have causes coral reefs to lose the algae that feed the coral polyps. When this happens, the coral reefs become ghostly white, or bleached. Sometimes the reefs can recover, but they often cannot. In 1998, the Pacific Ocean lost 16% of the world’s coral reefs due to high temperatures, subsequent to an el Nino event. In a survey of the area in 2005, species diversity had declined, with the reefs showing serious physical deterioration.

As societies continue to develop, human populations have consequently increased, exponentially. Ironically, this can make entire populations more vulnerable to dramatic shifts from climate change, as the risk potentials for major flooding, drought and wildfires impact their resources. In one recent and tragic example, over-logging and excessive deforestation eventually resulted in a catastrophic mudslide event that eliminated the entire village of Guinsaugo, Philippines. After 10 days of unusually heavy rainfalls, close to 1000 people loss their lives that day. However, it's unclear what role global warming may have contributed to this tragedy.

- In the table below, the IPCC 3rd Assessment Report of 2001 outlines several potential socioeconomic impacts of climate change on coastal regions alone:

Box 6-3. Potential Impacts of Climate Change and Sea-Level Rise on Coastal Systems
Related socioeconomic impacts can include the following:

• Increased loss of property and coastal habitats
• Increased flood risk and potential loss of life
• Damage to coastal protection works and other infrastructure
• Increased disease risk
• Loss of renewable and subsistence resources
• Loss of tourism, recreation, and transportation functions
• Loss of nonmonetary cultural resources and values
• Impacts on agriculture and aquaculture through decline in soil and water quality.

“Climate change can affect human health directly (ie. Impacts of thermal stress, death/injury in floods and storms) and directly through changes in the ranges of disease vectors (ie. Mosquitoes) , weather borne pathogens, water quality air quality,, and food availability and quality. ...”

-Global Climate Change may increase human mortality rates

Perhaps one of the most alarming findings on human impact by global climate change was reported last November in the journal Nature (Issue 438: 310-317, 2005) by Dr. Jonathan Patz and his collaborators at WHO . They revealed a strong association between climate change and human disease, resulting from cardiovascular and respiratory diseases, consequences of extreme heat waves, infectious diseases and crop failure. Patz et al. detailed significant mortality rates which now claims 150,000 lives annually.

Climate change will have an especially severe impact on sub-Saharan African populations and the poor. But it will also impact the elderly who are unable to acclimate to annual extreme or prolonged weather events, such as heat waves. This was evident following the 1995 Chicago heat wave, which claimed over 500 official deaths and the 2003 Paris heat wave, which claimed close to 15,000 lives, according to France's National Institute of Health and Medical Research.

-Global Climate Change may increase spread of disease-causing organisms

However, global climate change is already impacting human health by extending the host ranges of insects that can carry disease-causing organisms, such as malaria, West Nile virus, Lyme disease and encephalitis. The table below illustrates how the host range of mosquitoes that carry West Nile virus has spread from NE Canada to most every state of the continental United States and Canada in just 5 years.

-National security implications of global warming.

An argument often presented is that humans can readily adapt to climate change. However, this is only partly true. Historically, climate changes have caused serious incidents of famine, drought, flooding and disease that have more often contributed to the collapse of civilizations. As a consequence, it has resulted in mass migrations of populations, causing regional conflicts as populations (in part of whole) become environmental refugees. And although this is particularly serious for poverty-stricken communities in developing countries, which are incapable of committing their limited resources to confronting the resulting extensive needs of their people, we need not look beyond our own shores.

Here, the hundreds of thousands of American residents along the Gulf Coast and in the city of New Orleans became environmental refugees within their own country, as communities such as Houston and Baton Rouge became overwhelmed in trying to provide services and housing. But the consequences of Hurricane Katrina also exposed our vulnerabilities in national security. Ancient empires are believed to have capitulated in this manner, such as the Mayan empire. But the displacement of millions due to global warming will potentially occur on a global, rather than just a regional, scale, which, in turn, will present not only an internal security crisis for our nation, but also an international security crisis for the world as a whole.

Certainly, this post can not do justice to the enormous wealth of scientific data that has already been reported by researchers, analysts and “responsible” policy makers, who've collectively provided clear evidence of global warming and climate change. And although few have argued that climate change projections could alternatively offer some benefits, such impacts would be limited to specific regions. Furthermore, such “benefits” are clearly marginal when seen in the context of the enormous social, economic, and environmental costs that global warming could have on our future.

This is why Wes Clark conveyed that global warming presents a serious global crisis to our short term and long term national security interests. The impacts from global warming and climate change are abundantly evident now. Immediate action - from each of us and from our leaders in Washington - are needed to prepare, preserve and protect all that we value individually and collectively. For we already face some irreversible consequences, and we may face even more in the decades to come if we don't make the necessary changes now and in the near future to curb our contribution to global warming. Such change includes a realistic and full-fledged commitment from citizens and policy makers to the construction of a comprehensive energy plan that significantly addresses our need to reduce our dependency on fossil fuels.

As Wes Clark conveyed through his podcast, "Leadership and Global Warming”, it takes uncommon leadership to confront the adverse effects of global climate change. He made clear that what is urgently needed today is effective leadership as, together, we move toward a global energy strategy in coordination with the world community. This process starts at home. Americans must assume the responsibility to work together with each other and with our leaders, then together with the world community to initiate action in the coming years.

As many scientists have warned, we are at the "tipping point" of major changes; but it's up to us to define whether we, in this century, resolve our challenges posed by global warming or we let it drag us into global crisis.

• The Intergovernmental Panel on Climate Change (IPCC) makes their reports available on the web:

  http://www.ipcc.ch

• One of the best sources of scientific information is the website RealClimate, maintained by working climate scientists:

  http://www.realclimate.org/

• The Union of Concerned Scientists features valuable educational resources at their website, including various interactive multimedia features and advocacy petitions, which help enhance and empower its visitors on the issues of global warming:

  http://www.ucsusa.org/global_warming/