We don't see it, smell it, or even realize it's there most days but our atmosphere is what makes all life on this planet possible. Without it the oceans and lakes would boil and evaporate. Ours would no longer be a blue planet with cooling rains and warm breezes, but a scalding hot, freezing cold mass of lifeless rock orbiting a relentless sun. Earth's protective layer is a complex system of moving and shifting air currents that work in tandem with our oceans to regulate temperature and distribute precipitation worldwide. It gives us blue skies and sunsets, thunder and lightening. And like our oceans, we are just starting to understand the complex workings that allow our atmosphere to keep planet earth's temperature within livable range. It's so much more than just the air we breathe.

Greenhouse gases

Like an insulating blanket, our atmosphere keeps half the earth warm at night and shields the other half from too much sun in the day. Greenhouse gases are responsible for most of this beneficial insulating effect, keeping the sun's energy from radiating back into space. But since the start of industrial revolution, global temperatures have been rising at an unprecedented rate. The consensus among climate experts is that carbon dioxide, methane and other greenhouse gases given off from the burning of fossil fuels have added to our atmospheres naturally occurring carbon dioxide levels.

Fifty years ago, worldwide greenhouse gas emissions stood at 1.6 billion tons annually. Since then the numbers have more than quadrupled to 6.5 billion tons and show little sign of decreasing. Because the earth's capacity to absorb carbon dioxide is fairly constant, as emissions rise so does the amount of greenhouse gas in our atmosphere. In other words, the more we pollute, the dirtier our atmosphere becomes, and the hotter our planet gets.

Causes and culprits

So what are the causes? In the US, the major polluters of greenhouse gases are coal and natural gas fired power plants, which account for more than 40 percent of carbon emissions. Transportation, including airplanes, ships, and motor vehicles, accounts for 25 percent while manufacturing accounts for 20 percent. The remaining 15 comes from residential and commercial uses, such as wood burning fireplaces, gas powered lawnmowers, and commercial cattle feedlots.

Despite this, real progress toward reducing carbon emissions has been slow. Major auto manufacturers continue to resist efforts to establish higher minimum mileage requirements. Developing nations such as China and India are building coal-fired power plants in ever increasing numbers. And the US, with only 5 percent of the earth's population continues to be its biggest polluter, responsible for 33 percent of global carbon emissions. The average person living in the US adds 22 tons of carbon emissions to the atmosphere each year, dwarfing the global average of 6 tons per year. In every aspect of life, from heating and cooling our houses to the food we eat, Americans consume resources at rates far exceeding those of people even in modernized countries like Japan and Germany.

Life on earth

It is estimated that worldwide atmospheric CO2 levels will more than double or triple by the year 2100. The resulting change in average global surface temperatures will likely rise between 2.7 and 10 degrees Fahrenheit. What does this mean for us?

In the short term, it means we can expect more of what we've already been experiencing. Figures from the US National Oceanic and Atmospheric Administration show the ten hottest years on record have all occurred since 1990. According to meteorologists, the last thirty years have seen a 50 percent increase in the intensity and duration of tropical cyclones and hurricanes, which will draw energy from warm ocean water and cause massive destruction where they make landfall. 2005's hurricane Katrina is a precursor of what we can expect in the years to come.

We've already talked about large scale melting of the polar ice sheets. Worldwide, glaciers will continue melting at faster rates. Of the 150 original glaciers in Montana's Glacier National park, only 27 were left by 2005. If current warming trends continue, climate researchers estimate that by 2030, the park will have no glaciers left. The same can be said for almost all of the earth's alpine regions, where many people living in the valleys and plains below depend on seasonal flow of glacial melt water to survive.

Aside from violent weather and rising sea levels, global warming will also pose a threat to our ability to grow food. As our atmosphere warms, changes in the earth's climate patterns will force growing operations to either compensate for drought or move to different locations. To date, large-scale agriculture has been successful at increasing crop yields - mainly due to widespread irrigation and use of chemical fertilizers. But given that only 10 percent of the earth's land is considered arable, shifting crops northward to escape the excessive heat of lower latitudes will not be a viable option. As with clear cutting Amazon rainforest to plant soybeans for export, replacing vast areas of any ecosystem with large-scale monoculture crops can carry harsh consequences.

What we can do

The sky above us is shared space for all living things on earth. Carbon emissions affect the global population no matter where they come from. Just as air currents carry factory pollutants in China across the Pacific to the US, emissions from coal burning power plants in the US northeast drift across the Atlantic to Europe. In our atmosphere of upper level jet stream flows and trade winds, there is no such thing as an isolated problem, only shared responsibility.

- or - Considering how air pollution travels on jet streams and trade winds to all corners of the globe, there is no such thing as an isolated problem, only shared responsibility.

 

The challenges we face are staggering. But consider that with existing technologies, clean, renewable energy could easily supply the world's power needs. Each day, enough solar energy falls on the earth's surface to meet global demand for an entire year. There is more energy in just 20 days of sunshine than all our fossil fuel reserves. A recent study conducted by the US department of Energy and MIT concluded that the potential wind energy off the American coastline is equal to the output of all our power plants combined. Advances in hybrid car technology are allowing environmentally minded drivers to drastically reduce their fossil fuel consumption. Who knows what advances the future will bring?

On the small scale, an act as simple as replacing one incandescent light bulb with a compact fluorescent can eliminate 73 pounds of carbon emissions per year, not to mention the cost savings over the life of the bulb. When driving, charge your cell phones and PDA's as much as possible and save on the home power bill. We pay a high price in gasoline for all that power our car's alternators turn out, so why not make the most of it?  

Plugging in home electronic equipment to a power strip and switching it off when not in use eliminates the "trickle" of electricity that is drained even when not in use. In California alone, eliminating the trickle drained from unused appliances and electronics would cut the states electricity usage by 10 percent - enough savings to power Alaska, Rhode Island, Connecticut, and Massachusetts combined.