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HO Notesfor CPBio Climate Change part 2 geologic predictions Sept 27 2009 by VlFb8K9


									GLOBAL CLIMATE CHANGE - Mr. Nolan                                                Name: _________________

Global Climate Change notes (continued)
                           CARBON DIOXIDE AND TEMPERATURE
Over geologic time, there is a clear correlation between carbon dioxide concentration
and temperature, as shown in the graph below.

Over the past 800,000 years for which we have data, through numerous ice ages and
warming periods, the concentration of CO2 in the atmosphere has ranged between 180
parts per million (ppm) during the deepest glacial cooling periods, up to 280 ppm during
the warmest periods. This is worth repeating. For at least the last 800,000 years
carbon dioxide has been in the range of 180 to 280 ppm. However, due to human
fossil fuel burning, CO2 concentration has now reached 385 ppm! (FYI – Our
species has only existed for 150,000 years.)
    ppm Defined: A CO2 concentration of 385 parts per million means for every
       million molecules of air, 385 of them are CO2. This could be rewritten as
       0.000385 percent. Most of the rest of the molecules are nitrogen and oxygen.

What causes these geologic-scale cycles of heating and cooling?
Atmospheric temperature is directly related to the atmospheric concentration of carbon
dioxide, as shown in the graph above. But why were there big changes in CO2 and
temperature before humans evolved and eventually burned fossil fuels? Well, before
human impacts, variations in temperature and CO2 were caused by cyclical variations in
the amount of solar radiation that reached Earth. This has been caused mostly by
variations in Earth’s orbital patterns around the sun. During warmer periods when the
Earth is closer to the sun and receives more solar radiation, the warmed oceans
released more CO2 into the atmosphere. During cooler periods, more CO2 was
absorbed by the oceans. So, as oceans warm, they release more carbon dioxide. This
fluctuation in atmospheric CO2 has amplified the temperature variations caused by
cyclical variations of solar heating. However, these changes in orbit and temperature
take place gradually over many thousands of years, as described on the next page.

A Brief History of Ice Ages and Warming
Global warming started long before the "Industrial Revolution" and the invention of the
internal combustion engine. Our current geologic-scale global warming began 11,000
years ago as the Earth started warming its way out of the Pleistocene Ice Age-- a time
when much of North America, Europe, and Asia lay buried beneath great sheets of
glacial ice. Earth's climate and the biosphere have been in constant flux, dominated by
ice ages and glaciers for the past several million years. We are currently enjoying a
temporary releif from the deep freeze.

Approximately every 100,000 years Earth's climate warms up for 15,000 to 20,000
years before regressing back to a cold ice age climate. We are about 11,400 years into
our current interglacial warming period. Any slow cooling effects that may begin
sometime in the next few thousand years have no impact on the increases in GHGs and
temperatures Earth is experience now and for the next few hundred years.

These cycles of heating and cooling are due to cyclical change in the Earth’s orbit
around the sun. In a predictable pattern, the Earth gradually orbits closer or farther from
the sun. The most dominant cycle goes in 100,000 year cycles, from nearest to farthest
and back to nearest. The nearer Earth is to the sun, the more UV energy that reaches
the planet and the higher the temperature. Another orbital cycle is on a 26,000 year
period. Again, it is unrelated to the warming and CO2 increase of the last 150 years.

Variations in the Earth's Orbital Characteristics
100,000 year cycle
The orbit gradually changes from being elliptical to being nearly circular and then back to elliptical in a
period of about 100,000 years. Currently, the Earth is experiencing a period of more circular orbit. The
difference in the Earth's distance from the Sun between perihelion and aphelion (which is only about 3%)
is responsible for approximately a 7% variation in the amount of solar energy received at the top of the
26,000 year cycle
The second cyclical variation results from the fact that, as the Earth rotates on its polar axis, it wobbles
like a spinning top changing the orbital timing of the equinoxes and solstices The precession of the
equinox has a cycle of approximately 26,000 years. According to illustration A, the Earth is closer to the
Sun in January (perihelion) and farther away in July (aphelion) at the present time. Because of precession,
the reverse will be true in 13,000 years and the Earth will then be closer to the Sun in July (illustration
B). This means, of course, that if everything else remains constant, 13,000 years from now seasonal
variations in the Northern Hemisphere should be greater than at present (colder winters and warmer
41,000 year cycle
The third cyclical variation is related to the changes in the tilt of the Earth's axis of rotation over a 41,000
year period. During the 41,000 year cycle the tilt can deviate from approximately 22.5 to 24.5°. At the
present time, the tilt of the Earth's axis is 23.5°. When the tilt is small there is less climatic variation
between the summer and winter seasons in the middle and high latitudes. Winters tend to be milder and
summers cooler.

Temperature and Carbon Dioxide
Climate model projections summarized by the Intergovernmental Panel on Climate
Change (IPCC) and Britain’s Hadley Center indicate that average global surface
temperature will likely rise a further 3 °F to 13 °F during this century. The range of
values results from the use of differing scenarios of future greenhouse gas emissions as
well as models with differing climate sensitivity. The best estimate of the latest leading
models predict a 9oF global average temperature increase by 2100 if current
emissions trends continue (2008 & 2009 models from MIT, Princeton, and Britain’s
Hadley Center – MIT actually predicts 10oF increase by 2095). Britain’s Hadley Center
predicts that by 2060, temperatures over much of the U.S. could be 15oF to 18oF higher
than today in plausible worst-case emissions and feedback scenarios!

                           3 °F to 13 °F during this century
The Intergovernmental Panel on Climate Change (IPCC) projects that atmospheric
carbon dioxide levels could reach 450-550 ppm by 2050. Models they reference
indicate that carbon dioxide concentrations will be between 650 and 970 ppm by 2100
if humans don’t reduce emissions. The worst-case models show that carbon dioxide
levels could be 1,423 ppm by 2300 with a global temperature increase of 14.5°F
according to the U.S. Department of Energy’s Livermore Labs. This global average
involves less warming near the equator and much more near the poles. Warming at the
poles would exceed 68oF.

Sea Level Rise and Acidification

The most recent best estimate for sea level rise (SLR) are 5 feet for this century. This
doesn’t include single catastrophic ice flow events that could push levels much higher.

If the globe warms 14.5oF as listed earlier, the polar 68oF warming would cause melting
of most land-based ice (Antarctica, Greenland ice sheets, etc.) raising sea level by 260
feet, flooding approximately half the world’s population!

As oceans absorb the increasing atmospheric carbon dioxide, the oceans are becoming
more acidic (in the ocean some of the CO2 gets converted into carbonic acid). If
atmospheric CO2 reaches 1,400ppm, oceans will likely be so acidic that most sea life
would go extinct (See Livermore Labs article).

Although most studies focus on the period up to 2100, global warming and sea level rise
are expected to continue for more than a thousand years even if greenhouse gas levels
are stabilized.

Climate Feedback Loops
(e.g. Water Vapor, Ice Melting, Methane Release from Permafrost).

Earth is heating faster than climate models predicted as recently as 2006. Most climate
simulation models underestimated the impact of the climate feedback loops described

Positive climate feedback loops accelerate global warming as shown below.
      Warming  Evaporation  more water vapor (a GHG)  more warming  more
       evaporation  more water vapor  more warming…
      Warming  melting ice  Earth less reflective  more solar radiation absorbed
       by exposed land and water  more warming  more ice melting  more solar
       radiation absorption  more warming… * Simply put, ice is shinier than water. As
       more ice melts, the earth is less shiny, and so absorbs more solar energy. As
       shown on the next page, shininess is called albedo.

                           1979 Ice cap over northern hemisphere 2003
                                       source: NASA study
The Arctic Ocean ice is melting MUCH faster than predicted. And this just accelerates further warming!

     Warming  regional droughts  forest loss (die or burn)  more carbon dioxide
      left in the atmosphere  Warming 

 Living trees absorb carbon dioxide from the atmosphere during photosynthesis. Dead trees don’t!

     Warming  melting permafrost (long-term frozen soil, trapping gases and
      partially decayed organic matter covering 20% of Earth’s land)  more methane
      and carbon dioxide release into atmosphere  more warming  more melting of
      permafrost. [This is a HUGE deal. According to the National Center for
      Atmospheric Research in Boulder, CO, permanently frozen arctic soils hold
      approximately 200 – 800 gigatons of carbon. For comparison, the total human
      annual carbon output is only 7 gigatons (TIME, April 3, 2006, p 37).]

     Permafrost Cross-section below dashed line (see person on top for scale).




Predicted increased global temperature will cause:

      Sea Level Rise of 3 to 7 feet between 1990 and 2100 due to thermal expansion
       and glacial and ice sheet melting.

      Potential Catastrophic Sea Level Rise from collapse of massive West Antarctic
       ice sheets leading to 15 ft. sea level rise

      Complete melting of Greenland would raise sea levels by 23 feet

      Complete melting of all Antarctic ice alone would raise sea levels by 125 feet

      Melting of all last-based ice, possible with worst-case warming scenarios, would
       raise sea level approximately 260 feet.

      Glacial and Ice Melting (positive feedback loop)

      Thawing of permafrost, releasing methane in a positive feedback loop)

      Regional increased drought

      Regional increased flooding

      More Fires

      Increased Evaporation, Precipitation, & Storm Severity,

      Increasing deaths, displacements, and economic losses projected due to
       extreme weather attributed to global warming may be exacerbated by growing
       population densities

      Regional changes in water supply

      Changes in agricultural yields, trade routes

      Moving Populations

      Disease increases in the ranges of disease vectors

      Economic Impacts (Gross National Product Reduction, Insurance and Energy

      Shutdown of Thermohaline Circulation

      Ocean Acidification

      Lost and shifted ecosystems

      Increased species extinctions

Stunning new sea level rise research, Part 1: “Most likely” 0.8
to 2.0 meters by 2100
Sept 5, 2008 Climate Progress
Two major new studies, in Nature and Science, sharply increase the projected sea level
rise (SLR) by 2100. This post discusses the Science study, “Kinematic Constraints on
Glacier Contributions to 21st-Century Sea-Level Rise”, which concludes:
“On the basis of calculations presented here, we suggest that an improved
estimate of the range of SLR to 2100 including increased ice dynamics lies
between 3 and 7 feet.”

Needless to say, a sea level rise (SLR) of 5 feet by 2100 would be an unmitigated
catastrophe for the planet, even if sea levels didn’t keep rising several inches a decade
for centuries, which they inevitably would. The first meter of SLR would flood 17% of
Bangladesh, displacing tens of millions of people, and reducing its rice-farming land by
50 percent. Globally, it would create more than 100 million environmental refugees
and inundate over 13,000 square miles of this country. Southern Louisiana and
South Florida would inevitably be abandoned, especially in the face of a steadily
increasing number of killer super-hurricanes (see “Nature: Hurricanes ARE getting
fiercer — and it’s going to get much worse“). [A 1.5 meter SLR rise would bury 4
percent (420 square miles) of New Jersey!]

It could be much worse than these mainstream forecasts. A sea level rise of 13 feet this
century is “well within the realm of possibility,” according to John Holdren, president of
the American Association for the Advancement of Science. The Director for the Harvard
University Center for the Environment, Dan Schrag, agrees.

You must decrease U.S. global warming pollution by 80% by 2050 to
prevent the worst consequences of global warming! Most experts agree
that we cannot allow global temperature to increase more than 3.6oF above
preindustrial temperatures. With current knowledge, technology and laws,
so far GHG emissions have increased every year.

                   Why shouldn’t we approach this like a world war?
         Our national and global security and way of life is radically threatened!
In other world wars, men left their families and risked their lives to protect us from a
threat overseas; many women went to work outside the home for the first time in history;
families put their cars up on blocks; car factories were mandated to shift over to fighter
planes manufacturing; military spending skyrocketed – thousands of lives and insane
amounts of money were sacrificed. Now we refer to those Americans as “The Greatest
Generation” for their collective heroism.
1.       Why aren’t you at war?
2.       What will it take to put you at war and radically change your lifestyle? An 80%
          reduction in your emissions is radical!

        That’s 80% less clothing, driving, electronics consumption and use, heating,
         cooling and lighting. Or…, more likely, mandates to only use low emissions
         energy sources while radically reducing consumption of goods and meat.


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