Top 10 Concerns

Well ... and as shocking and deeply disturbing as these news are, the Pentagon, of all people, has finally begun to recognize that our escalating climatic extremes will result in unprecedented disasters as people around the world will fight desperately over massively failing food supplies and disappearing water - as I had first predicted in these pages [see "PREDICTIONS"], and ever since 1985 [see "ON THE RECORD"]. The preamble to the report "Imagining the Unthinkable", however, is a joke; it is here, apparently, only as a sop to a few dissenting scientists. How else can they say "the occurrences we outline would most likely happen in a few regions, rather than globally", when the report itself states, "abrupt climate change scenario could potentially de-stabilize the geo-political environment", and "Food shortages due to decreases in net global agricultural production", as well as "As global and local carrying capacities are reduced".
"The thermohaline circulation is a global ocean circulation. It is driven by differences in the density of the sea water which is determined by temperature (thermal) and salinity (haline). In the North Atlantic it transports warm and salty [heavier] water to the North. There the water is cooled and sinks into the deep ocean (cold water is heavier than warm water). [He forgot to mention that heavy sinking water in the North draws up light warm surface water from the South] This newly formed deep water is subsequently exported southward [which completes the circulation]. This slow (~0.1 m/s), but giant circulation has a flow equal to about 100 Amazon Rivers. Together with the Gulfstream it contributes (2/3 and 1/3) to the comparatively warm sea surface temperature along the coast of western Europe and to the relative mild European winters. Once the water are in the deep, they remain [sequestered] from the atmosphere for up to 1000 years." [Broecker, W., Chaotic Climate, Scientific American, November, 62-68, 1995]. The Southern Hemisphere has an equivalent thermohaline circulation, going in the opposite direction. Now then, the problem is that due to the warmer temperatures we are experiencing, [light] fresh water from melting ice at the Arctic and Antarctic is diluting the heavy salt water, which will eventually stop the sinking of water near the poles, and the thermohaline circulation will stop. This dilution of polar salt water with fresh water melt has been going on for the last 40 years, and is gradual at the moment. However, when the thermohaline circulation stops the climatic effect will be abrupt - practically overnight. Worse, and something which I have not seen considered anywhere, is the familiar phenomenon of Spring melting in the cold climates. At first, things begin to melt in the middle of the day, then as soon as the sun appears. But then, and all of a sudden, the next day all the snow is gone. I see no reason why this should be any different at the poles. There will come a day in the slow melting of polar ice, when, all of a sudden, and practically overnight, all the ice has melted and is gone. The consequences will be catastrophic - on a global scale.
Besides flooding vast low lying areas around the world, this means that no more warm surface water from the South is drawn northward, and those areas which have been warmed by this northward drawn water will experience far lower temperatures.

All this will result in a massive drop of the world's population - down to about 1/3 of its present numbers, and widespread disparate fighting over food, water, and places where survival is still possible. Here then, is the summary of the Pentagon report:

This will have far reaching consequences which will result in a fundamental change of our customary climates, resulting in a massive drop of global agricultural production, severe water shortages, prolonged droughts, flash floods and far more severe and far more frequent storms. And the world fisheries will be devastated as well.

And vast forest areas will disappear either due to extreme cold, or extreme heat, depending upon location, and due to lack of water. Vast conflagrations will accelerate this process. This in turn will severely change regional climates - essentially turning what once were forest climates into a desert climates.
There is substantial evidence to indicate that significant global warming will occur during the 21st century. Because changes have been gradual so far, and are projected to be similarly gradual in the future, the effects of global warming have the potential to be manageable for most nations. Recent research, however, suggests that there is a possibility that this gradual global warming could lead to a relatively abrupt slowing of the ocean’s thermohaline conveyor, which could lead to harsher winter weather conditions, sharply reduced soil moisture, and more intense winds in certain regions that currently provide a significant fraction of the world’s food production.

With inadequate preparation, the result could be a significant drop in the human carrying capacity of the Earth’s environment. The research suggests that once temperature rises above some threshold, adverse weather conditions could develop relatively abruptly, with persistent changes in the atmospheric circulation causing drops in some regions of 5-10 degrees Fahrenheit in a single decade. Paleoclimatic evidence suggests that altered climatic patterns could last for as much as a century, as they did when the ocean conveyor collapsed 8,200 years ago, or, at the extreme, could last as long as 1,000 years as they did during the Younger Dryas, which began about 12,700 years ago.

In this report, as an alternative to the scenarios of gradual climatic warming that are so common, we outline an abrupt climate change scenario patterned after the 100-year event that occurred about 8,200 years ago. This abrupt change scenario is characterized by the following conditions:

  • Annual average temperatures drop by up to 5 degrees Fahrenheit over Asia and North America and 6 degrees Fahrenheit in northern Europe.

  • Annual average temperatures increase by up to 4 degrees Fahrenheit in key areas throughout Australia, South America, and southern Africa.

  • Drought persists for most of the decade in critical agricultural regions and in the water resource regions for major population centers in Europe and eastern North America.

  • Winter storms and winds intensify, amplifying the impacts of the changes. Western Europe and the North Pacific experience enhanced winds.

    The report explores how such an abrupt climate change scenario could potentially de-stabilize the geo-political environment, leading to skirmishes, battles, and even war due to resource constraints such as:

    1) Food shortages due to decreases in net global agricultural production.

    2) Decreased availability and quality of fresh water in key regions due to shifted precipitation patters, causing more frequent floods and droughts.

    3) Disrupted access to energy supplies due to extensive sea ice and storminess.

    As global and local carrying capacities are reduced, tensions could mount around the world, leading to two fundamental strategies: defensive and offensive. Nations with the resources to do so may build virtual fortresses around their countries, preserving resources for themselves. Less fortunate nations especially those with ancient enmities with their neighbors, may initiate in struggles for access to food, clean water, or energy. Unlikely alliances could be formed as defense priorities shift and the goal is resources for survival rather than religion, ideology, or national honor.

    This scenario poses new challenges for the United States, and suggests several steps to be taken:

  • Improve predictive climate models to allow investigation of a wider range of scenarios and to anticipate how and where changes could occur.

  • Assemble comprehensive predictive models of the potential impacts of abrupt climate change to improve projections of how climate could influence food, water, and energy.

  • Create vulnerability metrics to anticipate which countries are most vulnerable to climate change and therefore, could contribute materially to an increasingly disorderly and potentially violent world.

  • Identify no-regrets strategies such as enhancing capabilities for water management.

  • Rehearse adaptive responses.

  • Explore local implications.

  • Explore geo-engineering options that control the climate.

    There are some indications today that global warming has reached the threshold where the thermohaline circulation could start to be significantly impacted. These indications include observations documenting that the North Atlantic is increasingly being freshened by melting glaciers, increased precipitation, and fresh water runoff making it substantially less salty over the past 40 years.

    This report suggests that, because of the potentially dire consequences, the risk of abrupt climate change, although uncertain and quite possibly small, should be elevated beyond a scientific debate to a U.S. national security concern.
    October 2003 [Environmental Media Services - http://www.ems.org/climate/pentagon_climate_change.html]