Scientific and Spiritual Dimensions of Climate Change

A Study Course
Class 8

Some More Climate Science


Planet Earth will continue to exist despite climate change, although in a much impoverished state, as there will be much less species of plants and animals. In the course of many thousands of years a rich biodiversity will probably evolve again on the Earth and the climate return to its natural cycles. The only question is whether human civilization will survive. Currently we are on a direct course to self-destruction.


Section 1: Historical Perspective

We know from earlier civilizations that the lead indicators of economic decline were environmental, not economic. The trees went first, then the soil, and finally the civilization itself. To archeologists, the sequence is all too familiar. i

Two Examples:
The ancient Sumerian civilization flourished on the central floodplain of the Euphrates River in the fourth millennium BC. The Sumerians had the first written language and built the first cities. They had a very productive agriculture with a sophisticated irrigation system. Unfortunately their irrigation system caused salination of the soil because of water evaporation. For a while the Sumerians could survive by planting more salt tolerant crops. However, their civilization collapsed and until today their once fertile land is almost a desert, with only little vegetation. ii

Easter Island in the South Pacific was settled around AD 400. Its civilization flourished on a volcanic island with rich soils and lush vegetation, including trees that grew 25 meters (82 feet) tall with trunks 2 meters (6,6 feet) in diameter. Archeological records indicate that the islanders ate mainly seafood, principally dolphins—a mammal that could only be caught by harpoon from large sea-going canoes. The Easter Island society flourished for several centuries, reaching an estimated population of 20,000. As its human numbers gradually increased, tree cutting exceeded the sustainable yield of forests. Eventually the large trees that were needed to build the sturdy canoes disappeared, depriving islanders of access to the dolphins and dramatically shrinking their food supply. The archeological record shows that at some point human bones became intermingled with the dolphin bones, suggesting a desperate society that had resorted to cannibalism. Today the island has fewer than 4,000 residents. iii

In other parts of the world, similar events happened in the past. A culture flourished. Population grew. Demand on the environment increased. Civilization reached a peak, then declined and collapsed because the environment could not sustain it any longer.

The situation today is unique because this time the whole planet is at stake and therefore civilization as we know it. "Our global economy is outgrowing the capacity of the Earth to support it, moving our early twenty-first century civilization ever closer to decline and possible collapse. ... We are consuming renewable resources faster than they can regenerate. Forests are shrinking, grasslands are deteriorating, water tables are falling, fisheries are collapsing, and soils are eroding. We are using up oil at a pace that leaves little time to plan beyond peak oil. And we are discharging greenhouse gases into the atmosphere faster than nature can absorb them, setting the stage for a rise in the earth’s temperature well above any since agriculture began." iv


Section 2: Future Threats

“The business-as-usual scenario yields an increase of about five degrees Fahrenheit of global warming during this century. How much will sea level rise with five degrees of global warming? Our best information comes from the Earth’s history. The last time that the Earth was five degrees warmer was three million years ago, when sea level was about eighty feet higher. Eighty feet! In that case, the United States would lose most East Coast cities: Boston, New York, Philadelphia, Washington, and Miami; indeed, practically the entire state of Florida would be under water. Fifty million people in the US live below that sea level. Other places would fare worse. China would have 250 million displaced persons. Bangladesh would produce 120 million refugees, practically the entire nation. India would lose the land of 150 million people.

"A rise in sea level, necessarily, begins slowly. Massive ice sheets must be softened and weakened before rapid disintegration and melting occurs and the sea level rises. It may require as much as a few centuries to produce most of the long-term response. But the inertia of ice sheets is not our ally against the effects of global warming. The Earth’s history reveals cases in which sea level, once ice sheets began to collapse, rose one meter (3.3 feet) every twenty years for centuries. That would be a calamity for hundreds of cities around the world, most of them far larger than New Orleans. Devastation from a rising sea occurs as the result of local storms which can be expected to cause repeated retreats from transitory shorelines and rebuilding away from them.” v

As if this was not enough, there are several issues that should prompt us to quick and effective actions:

The inertia of the climate system, the carbon sinks, and aerosol pollution have so far clouded the effects of climate change. Without these factors, the warming we would have experienced so far would have been considerably greater. Now, with the climate system changing to new patterns, carbon sinks reaching their limits, and (hopefully) aerosol pollution diminishing (with pollution control and reduction of fossil fuel burning), the warming will accelerate and its impacts become much more severe.

Feedback Mechanisms:

Many feedback mechanisms can accelerate the warming of the Earth. The following are the most important known feedbacks:
Any of these feedback mechanisms could bring the Earth's climate system to a tipping point. We don't know where that tipping point is. It's quite likely that the planet will cross over that threshold without humanity noticing. Once we will wake up to that reality, it will be too late because this is an irreversible process. Some scientists think that we are already close to that point. "Computer models of the Earth's climate suggest that a critical threshold is approaching. Crossing over it will be easy, crossing back quite likely impossible." x


Section 3: Present Challenges

“In spite of nearly 20 years of international attention, emissions of greenhouse gases continue to grow rapidly. As a consequence, the concentration of carbon dioxide in the atmosphere has increased faster during the last 10 years than at any time since continuous measurements began in 1960.

Unabated, current increasing trends in emissions can be expected to raise Earth’s temperature by a further 4-6°C (7.2-10.8°F), if not more, by the end of this century. If even half that much warming occurs, it will bring huge damages and potentially catastrophic problems.” xi

So far, the approach of political leaders when they consider cutting carbon dioxide emissions has not been effective at all, because their first concern has always been what is politically feasible. There must be a complete turn around: Actions need to be taken according to the reality of the threat, which means that they must be taken in accordance with science. What do scientists say about how much CO2 emissions must be cut to avoid irreversible climate change?

More recently, NASA climatologist James Hansen said that if we want to preserve creation, the planet on which civilization developed, CO2 levels need to be stabilized even lower, at 350ppm or below. xii “Halting the increase in global warming at far below 2°C (3.6°CF) is possible, and lowering global warming as rapidly as possible to below an increase of 1°C  (1.8°F) appears critical if there is to be a high probability of preventing dangerous climate change. The emissions reduction actions required to achieve this are massive and appear to be at the outer edge of what is technically and economically feasible. Scenarios that can start to get within reach of these temperature goals require greenhouse gas emissions to peak before 2020 and then to drop toward 85% below 1990 levels by 2050, with further reductions beyond this time.” xiii

It is an enormous task to reduce our emissions and to stabilize atmospheric CO2 levels. The world is moving rapidly towards the threshold of irreversible climate change. xiv As the threat of reaching a tipping point is becoming increasingly close, Nobel Peace Price winner Al Gore challenged the United States to “produce 100% of its energy from renewable energy and from truly carbon free sources within 10 years. xv

Many experts in the field believe that with a concerted effort it is still possible to avoid the worst scenarios of climate change. “It is encouraging to know that we now have the technologies to build a new energy economy, one that is not climate-disruptive, that does not pollute the air, and that can last as long as the sun itself. The question is no longer whether we can develop a climate-stabilizing energy economy, but whether we can develop it before climate change spins out of control.” xvi

REFERENCES
i      Lester R. Brown, Plan B 2.0: Rescuing a Planet Under Stress and a Civilization in Trouble (NY: W.W. Norton & Co., 2006), From Chapter 1. Entering a New World
ii     info: Lester R. Brown, Plan B 2.0: Rescuing a Planet Under Stress and a Civilization in Trouble (NY: W.W. Norton & Co., 2006), From Chapter 1. Entering a New World
iii    info: Lester R. Brown, Plan B 2.0: Rescuing a Planet Under Stress and a Civilization in Trouble (NY: W.W. Norton & Co., 2006), From Chapter 1. Entering a New World
iv    Lester R. Brown, Plan B 2.0: Rescuing a Planet Under Stress and a Civilization in Trouble (NY: W.W. Norton & Co., 2006), From Chapter 1. Entering a New World
v     “The Threat to the Planet” by Jim Hansen, Director of the NASA Goddard Institute for Space Studies and Adjunct Professor of Earth and Environmental Sciences at Columbia University’s Earth Institute.
vi    Assessing the Physical Science of Climate Change:  IPCC Working Group 1 (2007), From Material Presented by Susan Solomon, co-chair WG I at the Royal Society London, March, 2007 and Norwegian Academy
vii   info from Field Notes from a Catastrophe, Elizabeth Kolbert p. 21
viii  Field Notes from a Catastrophe, Elizabeth Kolbert p. 20
ix    Info from: Ian Sample, science correspondent, The Guardian, Thursday August 11, 2005  http://www.guardian.co.uk/environment/2005/aug/11/science.climatechange1
x     Field Notes from a Catastrophe, Elizabeth Kolbert p.3
xi    “A Safe Landing for the Climate” by W. L. Hare in State of the World 2009, p. 13, published by the Worldwatch Institute
xii   Global Warming 20 Years Later: Tipping Points Near, Jim Hansen, 23 June 2008, National Press Club, and House Select Committee on Energy Independence & Global Warming, Washington, DC.
xiii  “A Safe Landing for the Climate” by W. L. Hare in State of the World 2009, p. 29, published by the Worldwatch Institute
xiv  info: Field Notes from a Catastrophe, Elizabeth Kolbert p. 184/185
xv   July, 2008
xvi  Lester R. Brown, Plan B 3.0: Mobilizing to Save Civilization (New York: W.W. Norton and Company, Earth Policy Institute, 2008) From Chapter 12. Turning to Renewable Energy, THE WORLD ENERGY ECONOMY OF 2020  

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Last updated 10 November 2009
© Christine Muller and International Environment Forum