Across the Rockies - What is Global Warming?

The Basics

When fossil fuels like gasoline are burned, they emit carbon dioxide (CO2) into the atmosphere. CO2 is necessary for life on Earth and is produced in small amounts whenever you exhale. However, humans are burning so much fossil fuel that we are causing the temperature of the Earth to rise. CO2 is considered a "greenhouse gas" because it traps heat from the Sun that would normally bounce off the Earth and escape back into space. This produces a "greenhouse effect", or a warming of the Earth. The more fossil fuels we burn, the more CO2 we emit into the atmosphere, and the warmer the Earth gets. This human-induced "global warming" has serious consequences for our food supplies, our coastal communities, and the Earth's weather and ecosystems.

The Situation Now

CO2 reached 385 parts per million earlier this year, surpassing what NASA's head climate scientist James Hansen says is the "safe" level for atmospheric CO2 - 350 ppm. At current emissions rates, atmospheric CO2 will reach 450 ppm in less than 35 years. The Intergovernmental Panel on Climate Change (IPCC) stresses that this level is a tipping point beyond which irreversible damage will be done to the global climate regime. According to Tim Flannery, an Australian climate change expert, "The amount of greenhouse gas in the atmosphere is already above the threshold that can potentially cause dangerous climate change. We are already at risk...It's not next year or next decade, it's now."

The Consequences of Global Warming

According to Sir John Holmes, the United Nation's emergency relief coordinator and under-secretary-general for humanitarian affairs, a record number of floods, droughts and storms around the world in 2007 amounted to a climate change "mega disaster." "We are seeing the effects of climate change," he said. "Any year can be a freak but the pattern looks pretty clear to be honest...this is here and now, this is with us already." Two years ago only half the international disasters dealt with by OCHA, the UN Office for the Coordination of Humanitarian Affairs, had anything to do with the climate; this year all but one of the 14 emergency appeals is climate-related. The OCHA appeals represent the tip of an iceberg since they are launched only with the agreement of the affected country.

Time is Running Out

We only have a short window of time to quickly reduce our greenhouse gas emissions because our actions are kicking off irreversible changes in the way in which our planet processes global warming gasses. For example, the increased temperature caused by human-induced global warming is causing soil and the oceans to absorb less carbon dioxide, which speeds up global warming. In western Siberia, there is a frozen peat bog the size of France and Germany combined that is starting to thaw and could release billions of tons of methane, a greenhouse gas 20 times more potent than carbon dioxide, into the atmosphere. Changes like these are, in effect, kicking off a positive feedback system of planet-induced global warming that is irreversible once started.

"I don't think people realize, but we will have to live a life with zero carbon emissions."
-James Butler, Acting Director of the National Oceanic and Atmospheric Association (NOAA) Global Monitoring Division

What Can We Do?

So what can we do avoid dangerous levels of global warming? Climate experts generally agree that we need to aim for a global temperature increase of no more than 2 to 3 degrees Celsius by 2050. To achieve this goal, we in the US need to reduce our greenhouse gas emissions to between 60 and 80% below the 1990 level by 2050. Since CO2 accounts for 72% of all greenhouse gases emitted by human sources, one way to stop global warming is to reduce our C02 emissions. But how can we reduce our C02 emissions? The Across the Rockies team advocates the widespread use of alternative transportation modes such as biking, carpooling, public transit, and alternative fuel vehicles as a feasible way to reduce America's CO2 emissions and thus help stop global warming. Please visit our Why Alternative Transportation? page to find out more.