Knowledge of past climates and climatic change provides the baseline for interpreting today's climatic variations. But given that detailed weather records have been kept in this country for only about a century, how can one determine the climates of past centuries or eons? The answer lies in recently-advanced intricate research techniques for dissecting nature's climatic records. These are hidden within the Earth and the remains of its ancient inhabitants -- minute changes in concentrations of pollen for example, and rings formed during the growth of trees and stalagmites.

Margaret Davis (ecology professor at the University of Minnesota) studies pollen deposits from past millennia. Through identifying and counting each species' pollen grains, she is able to track and pace the long-term migration of trees - the westward movement of beech over thousands of years through Michigan and into Wisconsin, for example. Because each tree species inherits specific climatic requirements, tree movement tracks climate change. Davis pointed out that anthropogenic climate shifts will indeed force large-scale changes in tree distribution. The habitat for sugar maple, for example, is predicted to move hundreds of miles to the north. However, her studies have identified a major problem: rapid changes in temperature and moisture are likely to overwhelm trees' innate ability to disperse and reestablish forest communities.

Malcolm Hughes (Laboratory of Tree Ring Research, University of Arizona) and Luis Gonzalez (UI Geology Dept) explained their use of other natural barometers. Hughes, an expert in dendrochronology, is able to use the annual growth rings within the trunks of trees to determine and date the maximum temperature of a particular growing season, late winter moisture, and other weather traits. By cross-comparing his data with actual weather events, the growth of corals, and ice core samples, he has been able to reconstruct climate accurately for about the past 2,000 years. Using tree ring and other data collected from around the world, he is now attempting to recreate a global grid of annual temperature variations that dates from the present back through the 15th century. Gonzalez's intricate analyses of the calcite deposits that form stalagmites likewise can be used to determine climatic variations (see CGRER's 1998 Annual Report, page 12).

Is climate indeed changing as we watch? Precise and abundant climatic data are needed to answer this question. These voluminous data ideally feed into numerical models capable of reliably predicting future climatic trends.

While we have fairly good long-term measurements of surface temperature and precipitation, Witold Krajewski (Civil and Environmental Engineering and IIHR, UI) explained that these alone are far from sufficient for our needs. Analysis of the complex phenomenon that we call "climate" necessitates measurements of numerous external components (such as solar energy, trace greenhouse gases, and aerosols) and of feedbacks between the Earth and atmosphere, all of which influence temperature and precipitation. Uncertainties that creep into any measurement or transformation of any of these data sets can magnify inaccuracies in our climatic interpretations. The problems with collecting accurate and detailed weather data are thus major drawbacks to any interpretation of climatic change. To improve the situation, Krajewski emphasized that we need to develop a well-coordinated international commitment to collect data on numerous climatic variables, over a long time period, with sufficiently numerous and high-quality instruments.

Given the problems with collecting the raw data, how valid and significant are numerical models based on these data? The answer to this question depends on whom you ask. Warren Washington (head of Climate Change Research at the National Center for Atmospheric Research) stated that NCAR models now can accurately represent a number of climate-affecting features -- changes in greenhouse gases, sulfate aerosols, biomass burning, and even ocean currents (and thus El Nino) to name a few. The higher resolution made possible by more powerful computers is even allowing simulations of eddies in the Gulf Stream, although other features such as cloud cover are notorious for their uncertainty. Thus for certain climatic features (including tropospheric warming, sea ice and snow cover decrease, increased tropical water vapor, and increased nighttime temperatures), NCAR's models are now accurately representing measured and observed climate patterns.

The outspoken critic Richard Lindzen (meteorology professor at MIT) then drew the weaknesses of both weather observations and certain numerical models into a spirited challenge of current greenhouse gas theory. He stated that the importance of small increases in CO2 and other human-generated greenhouse gases are dwarfed by the warming effects of humidity and clouds, which are quite variable and complex to assess. Climate measurements may be only 30% accurate, and models of cloud cover are notably invalid. Thus probable errors in our climatic projections are larger than the greenhouse effect itself, Lindzen concluded, bringing into sharp focus the difficulties of drawing conclusions about complex climatic phenomena from masses of variably precise and accurate weather data.

Climate changes constantly of its own accord, and the results of these natural climatic changes are often quite obvious. Thus certain impacts of human-accelerated climate change can be enumerated with relative ease. The final panel summarized predicted impacts in three areas. Jonathan Patz (director of the Program on Health Effects of Global Environmental Change at Johns Hopkins) discussed probable shifts in human health concerns, such as more numerous deaths from heat stress in inner cities, northern movement of disease vectors such as malaria-carrying mosquitoes, and the complex production of "environmental refugees" fleeing devastation from sea level rise and other degradations of their homelands. These health-related concerns have been previously discussed in depth in IoWatch (spring and fall, 1997 issues). Herman Shugart, professor and director of the University of Virginia's Global Change Program, summarized the complexities and importance of modeling ecosystems to predict changes in vegetation - a challenge magnified by vegetation's ability both to respond to and create its own local climate.

David McGinnis (UI Geography Dept) described alterations in water resources expected from climate change. Models predict an enhanced hydrologic cycle, with more intense storms and global increases of 4-6% precipitation. Hydrologic patterns would also be affected by higher temperatures accelerating the melting of high-altitude snowpacks and glacier masses, a process already being observed. However precipitation patterns would vary greatly from season to season and place to place, as would environmental problems caused by these variations. In North America, increases in winter and spring runoff and decreases in summer moisture would increase the number of both floods and droughts. Nepal and other Himalayan countries are already concerned about the observed melting of glaciers; intensification of this melting would increase floods and landslides for a period, after which flow, irrigation supply, and hydropower would plummet. Social parameters - a growing human population and per capita water use - would also significantly affect the quality and quantity of available water.

The evening banquet speaker Joel Scheraga, who is Director of the U.S. Environmental Protection Agency's Global Change Research Program, described how EPA's assessment program is trying to maximize public input. Reiterating that the climate does indeed seem to be changing, and that the impacts and adaptations to such change can be significant, he then pushed forward into consideration of policy issues dealing with climate change problems.

Dorothy Paul of the Iowa United Nations Association - USA concluded the daytime portion of the symposium by reiterating the importance of political initiatives such as the Kyoto Protocols, which move us forward "an inch at a time." However Paul also challenged listeners to become players in transforming society and ourselves so that we shape a world habitable for our children.

Her call to invoke us all to work at the local and national level went out well beyond the walls of the symposium room. The symposium talks were broadcast live over the internet. In addition the symposium, along with the three other segments of the Climate Change program, are being summarized by Dorothy Paul. The summary, available in December, 1999, may be requested from: Iowa Division, United Nations Association - USA, 20 East Market St., Iowa City, Iowa, 52245, or by phone (319-337-7290) or email (unaiowa@inav.net).

While CGRER's climate change-related educational and research efforts continue, life proceeds as usual for most of the world. Which means that everything and nothing seem to be happening simultaneously.

On the one hand, levels of greenhouse gases continue to climb at an annual rate of about 0.5%. The evidence regarding global warming mounts year by year, although there is still some disagreement about how much of this warming is attributable to human activity.

On the other hand, the chance of the U.S. Congress voting to adopt the Kyoto Protocols (which would limit the rate of increase of greenhouse gas emissions) seems doubtful, even though other nations around the globe are moving forward with their own legislative limitations.

However other less comprehensive greenhouse gas-related bills have been introduced in Congress, and certain voluntary industrial initiatives related to carbon emissions appear to be moving forward. For example a growing number of industries have joined the Business Environmental Leadership Council, which is a part of the Pew Center on Global Climate Change. Members of the council accept that "enough is known about the science and environmental impacts of climate change for us to take actions to address its consequences," and council develops relevant policy studies in response. As CGRER's Jerry Schnoor explains, "We know that CO2 emissions are increasing. There's growing strong concern about an unstable atmosphere and climate variability. Industry is recognizing that it makes good economic sense to increase energy efficiency and decrease greenhouse gas emissions now, not later. Some industries believe that doing so will give them a competitive advantage in the future, and some industries are starting to act."

Two CGRER-related efforts serve to contrast this "all-and-nothing" scenario. CGRER members Dick Baker and Frank Weirich (both UI, Geology) accepted the Union of Concerned Scientists' invitation to join about 50 other scientists and visit Washington D.C. this past June, there speaking with legislative representatives and their aides about the science of global warming. While there, Dick became discouraged about the general lack of legislative concern regarding climate change, but he also stated that he was impressed by the Iowa legislators and their aides whom he visited. "We had been warned only to raise the most basic three ideas: 'Science demonstrates coming climate change, the implications of this are bad, and we need to do something about it.' However Iowa's congressmen were quick, involved, and asked their own questions," Dick stated.

On a more proactive note, Jerry Schnoor and his graduate student Richard Ney have been gearing up to assist with new industrial initiatives regarding greenhouse gas emissions. "There are no current regulations requiring reductions in greenhouse gas emissions," explains Richard. "However there's a real belief that these are coming. A new Des Moines firm, CQuest, has been formed to trade CO2 credits - in effect to broker the rights to emit CO2 between companies that produce little CO2 and those that produce voluminous quantities. CQuest just completed its first such sale. CGRER hopes to remain involved with greenhouse gas-reducing activities by providing scientific verification of emission reductions. We will be able to show that someone actually did reduce CO2 emissions, and by how much."