Greenhouse Gases:

There are several greenhouse gases in our Earth’s atmosphere that threaten our planet:

Carbon Dioxide (CO2) – the most abundant human-generated greenhouse gas in the atmosphere and it lasts for centuries.

Methane (CH4)  – This is 26 times more heat trapping than CO2 and it lasts for 12 years in the atmosphere.

Nitrous oxide (N2O) – Lasts for 114 years and has 216 times the potency of carbon dioxide.

For this discussion, we will focus on carbon dioxide because it is the largest threat to our planet due to the immense quantities of it that we pump into the atmosphere everyday

A healthy amount of CO2 is part of the natural balance of nature.  Just take a look at some of the natural cycles of CO2:

We breathe it out into the atmosphere  *  Plants absorb it from the atmosphere  *  Plants store it and release it into the soil *  We eat the plants and absorb it from them  * We breathe out some more into the atmosphere  *  The ocean absorbs CO2 from the atmosphere  *  Algae on top of the ocean absorbs CO2 *  Fish eat the algae  * and the cycles continue…

We need CO2 to survive, but what happens if we have too much?  Well, that is what is happening at a rapidly increasing rate today.  The largest contributor to an excess of CO2 in the atmosphere is from the burning of fossil fuels. 

If you’ve ever been to Epcot and gone on Ellen’s Energy Adventure, you may remember the story of fossil fuels.  About 300 million years ago, organic material was buried under the Earth’s surface by sediment, perhaps triggered by an earthquake or some other event.  Algae buried miles under the Earth by sediment eventually formed petroleum (a liquid).  Lush plants were also covered by sediment and baked in the heat of the Earth forming coal (a solid).  Swamp materials covered by sediment eventually created natural gas which is by the way, the least harmful of the three fossil fuels. 

So there we have the brief history of fossil fuels.  Why explain all of this?  Well, it helps us to understand it better when we think of all that organic material forming over 300 million years and how much CO2 is absorbed by the fossil fuels over that amount of time in the Earth.  Then if you imagine that we’ve taken that 300 million years worth of CO2 and released huge quantities of it into the atmosphere by burning it in a very short period in the history of time, it is easy to see how the chemical makeup of the Earth is way off balance.

Why is so much of it being released at once?  There are so many reasons.  We can start with the biggest bite of all – transportation.  Every time we step on the gas pedal or take a flight to New York, we release CO2 into the atmosphere.  And even though the United States emits more CO2 than any other country, there are an incredible amount of developing countries, such as China and India, that are quickly gaining on us as more and more of their residents are able to afford cars and other luxuries.

Did you also know that when you use electricity, you are burning fossil fuels?  When we turn on our light switch or crank up that AC, we are actually making a request of FPL to please burn more fossil fuels (oil, coal and natural gas) to generate the energy that we crave.  That’s why even if we are fortunate enough to afford those high electrical bills, it is better for the Earth and our children’s future on it to think about unplugging unused electronics and turning off those light switches (see “What You Can Do”).

Where does all the manmade CO2 come from?  Here are some global statistics:

            21% Residential – In our homes

            17% Commercial – At our businesses

            29% Industrial – In our factories

            33% Transportation – Cars, trains, busses, planes, ships

Other than burning of fossil fuels, the second highest contributor of CO2 into the Earth’s atmosphere comes from deforestation.  This accounts for 20% of the harmful CO2 that is emitted each year.  Every two seconds, we loose forest the size of a football field!  Illegal logging is rampant in South American rain forests.  Brazil now tries to control illegal logging with a new program, “Operation Arc of Fire” which consists of 48 police officers and 24 agents who patrol the forests with side arms and rifles.  They are spending $118 million in 2008 to crack down on illegal loggers but the challenges are daunting as they must cover 1.3 million square miles.  Thieves literally sneak into the rain forest and cut down trees to sell to lumber yards for cash.  From August 2007 to February 2008, an average of 270 square miles was forested per month in Brazil alone.  When these trees are gone, not only are they not there to absorb CO2 from the air, but also when a tree is cut down, it releases more CO2 into the atmosphere that was stored in the trunk and roots.

CO2 and Global Temperature

So why is it so bad that we’ve got too much CO2?  Well, an overwhelming majority of scientists today agree that there is a direct link between the excess CO2 levels and a global increase in temperature.

Scientists dug out a 2 mile tube of ice from the Antarctic which allowed them to study relationships over the last 650,000 years between CO2 levels in the atmosphere, temperature and sea level.  What they found was that it is entirely correlated.  If there is an increase in CO2, then there is an increase in temperature and sea level.  If there is a decrease in CO2, then temperature and sea level go down.  This pattern has remained unchanged for the last 650,000 years so we can figure that it’s pretty reliable!

Scientists also proved that an excess of CO2 causes a greenhouse effect.  The way this works is that light and heat are let in the Earth’s atmosphere from the sun and normally, the Earth reflects light and heat back out.  But when there is too much CO2, a barrier is created that doesn’t allow the heat to escape.  This heats up the Arctic ice and as it melts, there is less ice to reflect the light back out into space, creating more heat here on Earth.  That’s why they call the burning of fossil fuels “greenhouse gases” – because they make the Earth just like a greenhouse.

CO2 levels take hundreds of years to clear out of the atmosphere so even though that is just a blink in the history timeline of the Earth, the CO2 that we are releasing will be around for quite a while for us humans.  And although it is very normal for levels to go up and down because that has been going on for at least 650,000 years, it has NEVER increased this high, or this incredibly fast.  Greenhouse gases are measured to be around 384 parts per million which is scientifically proven to be unprecedented.  The highest point ever reached in the recorded history of the Earth was 300 parts per million and that was only reached once in the history of time.  The level of CO2 in the atmosphere before the Industrial Revolution was 280 parts per million which is an increase of 37% in less than 100 years.  Everyday, the increase is continuing to escalate at astounding proportions.  Scientists know that there is a “tipping point” beyond which point that change will come tumbling fast.  What that tipping point is and when we will reach it is not something that they can promise.