Our global energy system – the production, conversion, distribution and end use of energy – is dominated by fossil fuels. In 1995, fossil fuels supplied 97 percent of the energy for the transportation sector and 65 percent of the world’s electricity. (The remaining 35 percent of global electricity was derived from nuclear and hydroelectric generation.) Carbon dioxide (CO2), a gas created by burning fossil fuels like gasoline and coal, is the most abundant human-made greenhouse gas. Today, carbon dioxide concentrations are 30 percent higher than pre-industrial levels.

In 2002, coal burned at electric power plants in Wyoming generated 119 billion pounds of CO2. More than 105 billion pounds of CO2 were produced by burning nearly 22 million tons of subbituminous coal and more than two million tons of bituminous coal at these power plants.

Most scientists (including those employed by oil, gas and coal companies) now agree that human activities are largely responsible for the dangerous rate at which global temperatures are escalating. Forecasts predict that the Earth will warm 3 to 9 degrees Fahrenheit by the end of the century – a far greater rise than previously recorded global temperature fluctuations.

Evidence of global climate change is mounting. Massive ice shelves in Antarctica are calving into the sea. The snows of Mount Kilimanjaro are melting away. Storms and cyclones in the South Pacific are on the rise. The ice covering Greenland and the Arctic is shrinking. Wetlands and estuaries in the eastern U.S. are disappearing. Ice fields in the mountains of Alaska and Patagonia are thinning. Once-fertile lands in Africa and the Caribbean are turning into deserts. And glaciers perched on California’s Sierra Nevada Mountains and Wyoming’s Wind River Mountains are vanishing. But this growing evidence is being ignored by some of the world’s main producers of greenhouse gases, at the expense of the planet’s sustainable climate. Chief among them are the United States, Russia and Australia, all of which have refused to sign the 1997 United Nations Kyoto Protocol, which calls upon developed nations to reduce greenhouse-gas emissions by 5.2 percent of 1990 levels by 2012. Australia is the world’s highest emitter of greenhouse gases per capita, followed closely by the United States, the largest overall polluter on Earth.

The global increase in carbon dioxide emissions is a product of four variables: population growth, economic growth, energy intensity and carbon intensity. (Energy intensity means the amount of energy consumed per unit of economic output. Carbon intensity means the amount of carbon produced per unit of energy.)

If historic trends continue, future population and economic growth will greatly outpace improvements in energy efficiency. For example, a plausible – and alarming – prediction indicates that a doubling of the world’s population during this century, combined with an annual 1.8 percent growth in per-capita income, will yield a 12-fold increase in carbon dioxide emissions by 2100. Carbon dioxide emissions can affect the atmosphere for hundreds of years. Some of the carbon dioxide emitted in 1800 is still in the atmosphere – and today’s emissions will continue to influence the Earth’s climate a century from now.

Breakthroughs in energy technology are essential to stabilize greenhouse gas concentrations, improve energy efficiency, develop non-carbon energy sources and control energy costs. Scientists have identified three technologies that should receive the highest research and development priorities: carbon sequestration, hydrogen-based transportation and carbon capture, use and storage.

Carbon sequestration. This process removes carbon dioxide from the air by growing plants – which absorb the gas during photosynthesis — and then storing the carbon in grasslands, forests, soils or oceans. Today’s ranchers can increase carbon sequestration by reducing overgrazing and improving forage quality. Farmers can sequester carbon by reducing tilling and soil erosion, increasing crop rotation, adding vegetation buffers and planting trees.

Hydrogen-based transportation. This technology aims to convert passenger- transportation systems to fuel-cell vehicles powered by hydrogen instead of fossil fuels. Hydrogen fuel cells can power vehicles with greater efficiency and lower emissions than conventional gasoline and diesel engines. The greatest benefit would be achieved if hydrogen could be produced from non- carbon energy sources, such as the sun and wind.

Carbon capture and storage. This method centers on capturing carbon dioxide from fossil fuel combustion and storing it deeply in coal seams, saline formations, oil and gas reservoirs, basalt flows or oceans. Alternatively, captured carbon dioxide could be used to enhance the recovery of oil, and possibly to enhance the production of coalbed methane, urea, methanol and soda ash. Today’s capture technology is expensive and therefore not yet available for large-scale projects.

Without a doubt, global climate change is one of the most complex of the environmental, energy, economic and political issues confronting the international community. Recognizing this fact, more than 180 countries – including the United States – have ratified the United Nations Framework Convention on Climate Change, a vital outcome of the 1992 Earth Summit held in Rio de Janeiro. The ultimate objective of this treaty is to achieve “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.”

Stabilizing atmospheric concentrations of carbon dioxide and other greenhouse gases demands that we reduce current levels of global emissions. So, let’s get to work and undo global warming!