by Hilary Franz

These days it is difficult to open a newspaper without finding some discussion about climate change. It appears that Congress is also finally waking up and taking notice. Right now there are a number of bills in Congress on the issue. The following graph illustrates how the different legislative proposals, as well as the Bush administration policy and the Kyoto Protocol if it had been ratified, would address U.S. Carbon dioxide (CO2) emissions. Interestingly, the graph also provides a “business as usual” scenario, without any policy decisions, based on U.S. Department of Energy’s Energy Information Administration. The blue area shows the estimated range of U.S. emissions reductions that are necessary to stabilize global atmospheric greenhouse gas concentrations between 450 and 550 ppm (parts per million) CO2 equivalent.

Over 20 years ago, two scientists, Syukuro Manabe and R. T. Wetherald, made the first global climate model calculations of warming due to increased CO2 emissions. Their calculations were presented in congressional testimony in 1988. That same year, Dr. James Hansen, head of NASA’s top institute studying the climate, also warned Congress, testifying that he had 99% certainty that warmer temperatures were not the result of natural variation but the result of burning fossil fuels, solidifying scientific concern for human-caused global warming. The response by politicians and scientists was to conduct more research. In 1995, the scientists and governments brought together through the United Nations’ Intergovernmental Panel on Climate Change (IPCC), issued a report asserting that “the balance of evidence suggests” that human activity was altering the Earth’s climate, increasing its temperature. The report stated that human population had grown so large along with its energy needs that it was damaging the Earth’s natural systems, including its incoming and outgoing solar energy. Other countries found the science convincing and began responding. Yet, in Washington D.C. there was still no action on the issue.

We can breathe a bit of relief that the question these bills present is no longer whether global warming is occurring. (Towards this recent enlightenment, the arrival of the IPCC’s Fourth Assessment, which concludes that there is better than a 90% chance human beings have increased the average global temperature by about one degree.) Instead, the question is “How soon do we have to reduce our carbon emissions and by how much?” Without answering this question, it is difficult to determine which bill is the right one to support.

The most recent 2007 IPCC report, the Fourth Assessment Report (AR4), confirms the IPCC’s earlier report in stating that if we don’t take aggressive measures to curb fossil fuel emissions immediately, then we will see temperature increases of roughly 3° – 7°F during this century, with a wider range of about 2° to 12°F possible. Dr. Hansen has said that temperature increases of even 2 to 3 degrees Celsius will result in our “producing a “totally different planet” – a planet warmer than any our human ancestors have experienced. Hansen has given us a brief window of approximately 10 years to deal with climate change to avoid our remake of a “different planet.”

We can already know in part what the “different planet” will look like, as we have started to see the indicators. Typhoons and hurricanes will likely become more intense, with higher peak wind speeds and heavier precipitation. Extreme heat, heat waves, and heavy precipitation will become more frequent. Ice sheets will melt quickly, causing a rise in sea levels that would cover significant areas of land. Recent reports show that the Arctic may be close to a tipping point already, in that we will see year-round ice disappear very rapidly in the next few decades. The scientists already attribute the melting of 38,000 square miles of sea ice (an area the size of Alaska) to greenhouse gas emissions as well as the natural variability of Arctic ice. Indeed, new computer modeling shows that the Arctic may be free of all summer ice by as early as 2040. This would not only mean higher sea levels, but also the Earth would lose a major reflective surface, absorbing more solar energy, and potentially accelerating climate change.

In addition to sea level rise, the world would see the likely extinction of 50 percent of the Earth’s species. Extinctions are already occurring as a result of various stresses, largely human-made. Climate change is just one of them. A recent study, published in the journal Nature, presents compelling evidence that climate change has already wiped out a large number of species and would likely wipe out more. The study documents for the first time a direct correlation between global warming and the loss of around 65 of the 110 amphibian frog species in Central and South America. Increased temperatures are also threatening plant and fish species, including coral reefs and the South African rhododendron. Historically, species could largely survive shifts in climate, but as a result of human activity changing the landscape, animal and plant species find themselves stuck in fragmented natural habitat islands. As a result, plants and animals attempting to migrate in response to climate change, find their paths blocked by human constructed obstacles, or in the case of the polar bear, by melting ice.

The world is already facing irrevocable climate changes and impacts. The present CO2 concentration has not been exceeded during the past 420,000 years and likely not during the past 20 million years. Greenhouse gases in the atmosphere is already at 390 ppm CO2 emissons from 388 ppm a year ago, and this number is rising at roughly 2.5 ppm every year. (The total greenhouse gas emissions – CO2 and non-CO2 – is at around 430 ppm.) This is far above the 270 ppm level seen before the Industrial Revolution in the 18th century. This 2 ppm annual increase is a doubling from that just a few decades ago.

The impacts of climate change are dependent on both the final stabilization level and the path to reaching stabilization. Climate change and its impacts will grow more severe unless greenhouse gas emissions are stabilized. The IPCC points out a disturbing fact about greenhouse gas emissions: given the long life of gases there is a time lag between carbon emissions and their effects on temperature. This means that even if we halt the increase in coal, oil and gas burning at this very moment, temperatures would continue to rise about .2°C per decade. If we take no action to reduce emissions, the IPCC concludes that there will be twice as much warming over the next two decades. On the other hand, the IPCC concludes that “if all radiative forcing agents [greenhouse gases] are held constant at year 2000 levels, a further warming trend would occur in the next two decades at a rate of about 0.1C per decade.”

What this reveals is that if we had heeded the earlier warnings of the scientists even as late as 2000 and had done the work to reduce CO2 emissions, the temperature increase would be half as much as it is now. The fact is that everyday we continue to emit greenhouse gases, everyday we delay taking action to mitigate and reduce greenhouse gases, we pay a “procrastination penalty” that increases with each year of inaction. Thus, the earlier we lower emissions, the lower the stabilization level. The lower the stabilization rate, the lower the overall temperature increase. The lower the temperature increase, the less severe the world changing impacts.

Current evidence recommends aiming for final stabilization somewhere within the range 450-550 ppm CO2 emissions. For developed countries, like the United States, this means reducing emissions in the range of 80% below 1990 emissions by 2050 to reach 450 ppm, or 60% for 550 ppm. “A comparison of Approaches for International Climate Policy Post 2012” by Nicholas Hoehne of ECOFYS.

It is important to note that a scientific assessment at the 2005 international Avoiding Dangerous Climate Change conference concluded that at the level of 550 ppm it was likely that 2 degrees C would be exceeded. Moreover, stabilizing at 450 ppm would only result in a 50% likelihood of limiting global warming to 2 degrees Celsius. It concluded that to get a relatively high certainty of not exceeding 2 degrees Celsius we would need to achieve stabilization below 400 ppm. With an average of about 2 ppm per year, the projections have shown that we are likely to reach 400 ppm by 2016, 450 ppm by 2041, and 550 ppm by around 2091.

Delaying action now means more drastic emissions reductions later as evidenced in the McCain-Lieberman and Oliver-Gilchrist bills. Whereas, as seen in the Sanders-Boxer-Waxman and the Kerry-Snowe bills, taking early action, will allow the decline to occur more gradually. It is important to note that if action is slow and the emissions continue to rise, the ultimate level of stabilization will likely be higher (meaning over 550 ppm) and give less margin for error, making the world more vulnerable to unforeseen changes in the Earth’s system. Scientists over the last 10 years are continually discovering the natural CO2 sources and sinks out there (wetland bogs, ocean waters, etc.) and their related feedback loops. These natural sources and sinks present large margins of error, such that a slow start could have significant meaning. Whereas, if early and ambitious action is taken, there is an opportunity for adjustment if necessary. Indeed, under one study, temperatures associated with the delayed action path rose at more than twice the rate of the path where immediate action was taken. Under this scenario, many systems would be impacted by the increased temperature, with the most obvious one being our ecosystem and the species it supports, which may be unable to adapt.

As this debate has ensued, it is clear that steps must be taken immediately. Back in 1974 we averted a similar crisis where CFCs were found to be destroying the stratospheric ozone layer that protects animal and plant life from the sun’s ultraviolet rays. It is said that if we had continued “business as usual” growth of CFCs for just one more decade, the ozone layer would have been depleted to such a level that CFCs would have caused a larger greenhouse effect than CO2. As a world we took a different course. As a result CFCs are now decreasing and the ozone layer is recovering.

It is time again for the United States to rise to the challenge and take strong action to limit our CO2 emissions. Action must be prompt, otherwise CO2-producing infrastructure that may be built within a decade will make it impractical to keep further global warming under the stabilization level. In this case we have a global responsibility to do so. Of all the CO2 emissions produced from fossil fuels, the United States is responsible for approximately 25 % even though we make up only 5% of the population. This is most troubling given the IPCC’s upcoming report, which predicts billions of people could be affected by exacerbated problems in drinking water supply, sanitation, and drought, increased heat stress mortality and vector-borne diseases, and decreased food production in the tropics and subtropics. Most of these effects are negative for the most vulnerable developing countries.

For over 20 years we have ignored the warnings. It is time Congress take heed of these warnings and take immediate steps to reduce the Country’s CO2 emissions. We have already waited too long. “Business as usual” is no longer a viable course.