The earth is getting hotter. Ocean levels are rising, glaciers are shrinking, dust is blowing and new chemical concentrations are filling the atmosphere. How much hotter is the earth? The globe averages only one degree Fahrenheit warmer than it was 100 years ago. Is that a big enough change to start worrying?

Despite all of the attention and scientific research focused on global warming over the past 50 years, it’s impossible to know if the future is as disastrous as some people are saying.

The first thing to understand is our planet is naturally warm because of the greenhouse gases in the atmosphere. Greenhouse gasses include water vapor, carbon dioxide, ozone and methane, among others.

According to the Energy Information Administration, a government agency, greenhouse gases freely allow heat from the sun to pass through the atmosphere to the earth. When some of this heat is reflected back into the sky, the greenhouse gases trap it, preventing extreme cooling.

When greenhouse gasses are denser, the warming effect increases. This happens commonly, like when cloud cover creates warmer nights and traps heat close to the ground.

Climatologists fear the amount of greenhouse gases such as carbon dioxide and methane sent into the atmosphere causes global warming. Sources of these gases are industrial factories, vehicles and domestic fuel use. It’s impossible to know exactly how these gases are affecting the temperature of the earth.

But recent history shows a strong positive correlation between the rise of greenhouse gases and the rise in global average temperature (over the past 1000 years average global temperatures fluctuated only a fraction of a degree).

How much pollution are we putting in the air? In 1997, 1,780 million metric tons of carbon dioxide were emitted into the atmosphere from the United States alone, according to the National Academy of Sciences.

The basis behind the argument is that humans are responsible for global warming on two important facts: greenhouse gases trap heat, and humans are filling the sky with them.

One of the strongest arguments against associating air pollution with global warming is the earth’s natural cooling and warming cycle. Samples from ice, coral and old growth tree rings tell a lot about the climatic conditions of the past. There have been at least two ice ages, each followed by a global warming period. Based on past extreme climates, the earth has a mild temperature today.

Perhaps the gases aren’t responsible for the world’s extra degree Fahrenheit. Maybe they haven’t caused global warming — yet. The fuel thirsty planet hasn’t curbed its appetite, and there is more heat-retaining carbon in the atmosphere than ever in earth’s history.

Climatologists fear that the earth may have already passed its “tipping point,” referring to the irreversible condition of toxin concentrations in the atmosphere, according to Avoiding Dangerous Climate Change, a British report available at www.defra.gov.uk.

Rexburg residents might be excited about warmer winters, but the effects to the earth could be devastating. If the greenhouse effect is truly being increased by human involvement, expect the destruction of entire coral reef ecosystems, disappearance of coastlines and expansion of deserts, according to Conservation Frontline.

These projections are frightening, but their correlation to human activities is, by nature, impossible to prove.

While we can’t definitively connect humans with global warming, we know that humans are changing the composition of the atmosphere with chemicals whose properties we understand well. Our planet is changing, and we are changing it.