G L O B A L C L I M A T E C H A N G E
Duality: A situation or nature that has two states or parts that are
complementary or opposed to each other -Encarta Dictionary.






There is so much debate, even among






scientists, as to the effects humans






are having on the global ecosystem.






Whether you are observing the crazy






weather, sitting in traffic on the






freeway, or overlooking an amazing






view of the Santa Rosa —Petaluma






Valley only to look through a layer of






smog, most of us sense that
Most scientists are now accepting the fact that there is a global warming taking place. The majority of those scientists are satisfied Enough with the evidence to point the finger at human actions.
Historically, human activities released very few gases into the atmosphere, but since the Industrial Revolution, big increases in population growth, fossil fuel burning, and deforestation have all affected the mixture of gases in the atmosphere. Of special concern is the buildup of “greenhouse gases” which prevent heat from escaping the earth’s atmosphere and thus lead to an increase in the Earth’s temperature.
To what degree the Earth’s climate is changing is not certain, but it certainly seems to be because of us. It is now believed that in addition to the release of greenhouse gases, there is a second outcome of our actions which has the opposite effect of global warming.
Global Dimming describes the reduction in the amount of solar heat that is reaching the earth’s surface. The effect varies by location but over three decades (1960- 1990) there has been an estimated worldwide reduction of about 5% in the amount of sunlight that is reaching the earth’s surface. Among other effects, the reduction in solar energy can result in cooler daytime temperatures.
What is causing Global Dimming? One cause comes from the effects of our air pollution on clouds. Just like the sun reflecting off a lake, clouds can act like mirrors in the sky that reflect the sun’s light back into space (the opposite of what greenhouse gases do). Clouds naturally form when tiny molecules of water attach onto small particles in the air (such as floating pollen). But instead of attaching onto natural particles (like pollen), water is now attaching itself to man-made air pollution and when this happens, smaller droplets form in greater numbers.
This is just like increasing the number of tiny mirrors in the sky. In fact, these polluted clouds are up to six times more reflective than unpolluted ones. By reflecting more sunlight back into space these more reflective clouds cut down the sunlight reaching the Earth’s surface - hence contributing to global dimming.
Also, just like clouds, those vapor trails
you see behind an airplane reflect the
sun’s rays away from earth back into
space. It may sound odd, but one
reason that we now know this is be-
cause of “Sept. 11th.” After the attacks,
all airline flights were grounded.With no
airplanes in the sky, and no vapor trails
polluting the air, scientists found that
Temperatures actually went up.
Scientists attributed this to the global
dimming affect of vapor trails.
Recent research shows that global dimming has been masking the true impacts of global warming. This means that global warming is much worse than we thought. The scientists could not “feel” this effect with 






their scientific instruments because global dimming was offsetting the effects. As global dimming declines, the effects of global warming will exponentially increase.
Global dimming, which is
the gradual decrease in the
amount of sunlight and
solar energy reaching the
earth's surface, is caused
mostly by man-made air
pollution like smog. Global
warming, which is the
gradual increase in the
earth’s surface temperature,
is caused mostly by green-
house gases from the
burning of fossil fuels.
One of the main effects of
global dimming, which is the
exact opposite effect global
warming has, is that it
lowers the earth’s
temperature. For this
reason, scientists now
believe that for the past 40 years, global dimming has been masking the true effects of global warming.
What this means is that the earth’s surface temperature is almost certainly more sensitive to increases in greenhouse gases and
global warming is more immediate than we had thought.
We are learning how to fix some of the problems that are creating global dimming, but fixing the global warming will be much more difficult. There are many climate models that try to estimate how much the earth’s temperature will rise in the next 100 years due to the burning of fossil fuels.
There are a lot of factors that go into these calculations, but most models seem to average an increase of about 5 degrees F by 2100.
As if that were not a big enough problem, when that 5 degree estimate is adjusted for global dimming (remember, global dimming has been hiding the true effects), the number rises, possibly up to 10 degrees! With that kind of a change in temperature, sea levels will rise and towns like Petaluma could be underwater, while many parts of the world would be uninhabitable.
What can you do?
At the national, local and global level, change is taking place to address this problem but the United States is the number one polluter of greenhouse gases.
The United States is the number one polluter of greenhouse gases and will thus need to take the lead in reducing global levels. Although laws and technologies will continue to appear in order to achieve this goal, it is up to each of us to reduce our own emissions.
There are 4 main areas where you may be able to make improvements:
On the road: As tribal members learned at our Coping with Cars workshop, you can reduce emissions and save money by running all you errands at once, carpooling, keeping your car tuned up, and properly inflating your tires.
Recycle: Make sure all your recyclables make it to the right recycle bin; look for food wrapped in recycled packaging, and buy goods made from recycled materials.
In the Home: Save money by turning off lights when you are not in a room, insulating your home, and replace old appliance with newer energy efficient appliances (look for the Energy Star label).
In the Yard: Strategically plant trees in your yard to provide shade in the summer and added shelter from the elements in the winter to reduce energy bills and save money. Trees also store carbon and produce oxygen.
Remember, you do make a difference. You are adding to the levels of greenhouse gases and thus adding to global warming. Why not lessen your load, and save money doing it?