The Heat Is Online

Playing Truth Squad with ExxonMobil's Op-Ad (March, 2000)

An ExxonMobil ad on the Op-Ed Page of the The New York Times, March 23, 2000 titled "Unsettled Science" grossly distorts the January report of the National Research Council. Below are assertions by the ad (in italics)-- and responses from the science (in boldface).

(Fm Exxon-Mobil Ad)

Knowing that weather forecasts are reliable for a few days at best, we should recognize the enormous challenge facing scientists seeking to predict climate change and its impact over the next century. In spite of everyone's desire for clear answers, it is not surprising that fundamental gaps in knowledge leave scientists unable to make reliable predictions about future changes.

(Response): While weather is too variable to forecast for more than a few days, a consensus of more than 2,000 scientists from 100 countries agree that the earth's temperature will continue to rise as the buildup of atmospheric carbon from our coal and oil burning -- which is already at levels not seen in the last 400,000 years -- continues to rise.

Scientists have indeed made reliable predictions. Many of the most serious impacts of global warming predicted for years are being proved true by current conditions:

Prediction: global warming will happen due to an increase in greenhouse gases:


· the eleven hottest years on record have all occurred since 1980

· 1998 replaced 1997 as the hottest year ever recorded

· the decade of the 1990s is the hottest of the millennium

Scientists have long been concerned that warmer temperatures will cause a wide array of serious changes. Just some of these predictions and the evidence that shows the predictions to be correct:

Prediction: Change in seasonal cycles. Evidence: in many areas of the world, spring starts a week earlier and winter comes a week later.

Prediction: Glaciers and Icebergs will melt. Evidence: Glaciers are melting in the US and around the world, in some cases retreating by miles. Enormous chunks of ice shelf are breaking off from Antarctica.

Prediction: Sea levels will rise due to warmer oceans and ice melt. Evidence: ocean temperatures have increase and sea-levels are on the rise  about 4-10 inches so far this century.

(Fm Exxon-Mobil Ad)

A recent report from the National Research Council (NRC) raises important issues, including these still-unanswered questions:

(1) Has human activity already begun to change temperature and the climate, and (2) How significant will future change be?

(Response): The report from the NRC specifically does not address these questions. The NRC chose to focus only on a slight discrepancy between surface and satellite temperature records. The NRC specifically excluded from its study whether or not the rise is due to human activities -- a fact which was affirmed by 2,500 scientists from 100 countries in 1995 -- and which has been supported by a number of increasingly robust studies in the last five years. The NRC also excluded any future assessments from the scope of its recent study. The Exxon-Mobil Ad's statement regarding the NRC findings is akin to saying that Einstein's proof that E=MC2 fails to address the issue of whether or not heat rises.

(Fm Exxon-Mobil Ad)

The NRC report confirms that Earth's surface temperature has risen by about 1 degree Fahrenheit over the past 150 years. Some use this result to claim that humans are causing global warming, and they point to storms or floods to say that dangerous impacts are already under way. Yet scientists remain unable to confirm either contention.

(Response): Findings by the National Climatic Data Center published in the March 1,2000 issue of Geophysical Research Letters notes that while earth's temperature rose at a rate of 1* per century F. over between 1900 and 1970, it has been rising at the rate of 4* per century since 1980. A study by Drs. Michael Mann, Malcolm Hughes and Raymond Bradley (Geophysical Research Letters, March 15, 1999) found that the decade of the 1990s was the hottest at least in the past millennium. And studies by researchers at the National Oceanic and Atmospheric Administration's National Climatic Data Center verified an alteration in rainfall patterns, more severe droughts, stronger storms, more heat waves and the fact that we are getting more of our precipitation in intense, severe downpours than we did 20 years ago because of the buildup of emissions from coal and oil (Scientific American, May, 1997).

Contrary to the Exxon-Mobil Ad, the chief meteorologist of the United Kingdom and the head of the US National Oceanic and Atmospheric Administration, citing the torrential rainstorms which killed 15,000 people in Venezuela, last December called the climate crisis "critical" and urged the world to begin immediately to reduce it's burning of fossil fuels.

(Fm Exxon-Mobil Ad)

Geological evidence indicates that climate and greenhouse gas levels experience significant natural variability for reasons having nothing to do with human activity. Historical records and current scientific evidence show that Europe and North America experienced a medieval warm period one thousand years ago, followed centuries later by a little ice age. The geological record shows even larger changes throughout Earth's history.

(Response): While prehistoric greenhouse gas levels have experienced wide fluctuations, they were stable for 10,000 years at 280 parts per million until about 100 years ago, when the world began to burn more coal and oil. The Intergovernmental Panel on Climate Change was charged by the United Nations in 1988 with finding the reason for the sudden and rapid temperature rise beginning around 1900. In 1995, they declared definitively it was due to "human activity" in the form of fossil fuel emissions. That followed seven years of research by the largest international scientific collaboration in history in which researchers accomplished a series of experiments that distinguished human-induced warming from natural variability.

(Fm Exxon-Mobil Ad)

Against this backdrop of large, poorly understood natural variability, it is impossible for scientists to attribute the recent small surface temperature increase to human causes.

(Response): Findings by Mann, Bradley and Hughes (Geophysical Research Letters, March 15, 1999) noted that between the year 1000 AD and 1880 the planet experienced a slight cooling trend. That 880 year trend reversed abruptly as the world began to industrialize. Since that time, temperatures have been rising at a rate not seen in the last 10,000 years.

In the June 10, 1999 issue of the peer-reviewed journal, Nature, researchers from the British Meteorological Office in Bracknell reported: "The temperature changes over the twentieth century cannot be explained by any combination of natural internal variability and the response to natural forcings alone." The only explanation, they conclude, is the human output of oil and coal emissions.

(Fm Exxon-Mobil Ad)

Moreover, computer models relied upon by climate scientists predict that lower atmospheric temperatures will rise as fast as or faster than temperatures at the surface. However, only within the last 20 years have reliable global measurements of temperatures in the lower atmosphere been available through the use of satellite technology. These measurements show little if any warming.

(Response): In the peer-reviewed Journal, Nature, August 13, 1998, researchers found the satellite records to have been distorted because researchers failed to account for orbital decay which distorted satellite temperature findings. When the record was corrected to account for that decay, the satellites confirmed the warming trend. The NRC findings of January, 2000, confirmed that surface observations of recent warming are, indeed, real, according to Dr. John Wallace, professor of Atmospheric Sciences at the University of Washington, who chaired the NRC panel.

(Fm Exxon-Mobil Ad)

Even less is known about the potential positive or negative impacts of climate change. In fact, many academic studies and field experiments have demonstrated that increased levels of carbon dioxide can promote crop and forest growth.

(Response): Current research indicates that while plant fertilization by carbon dioxide may increase plant growth in the short-term in the Northern Hemisphere, it ultimately weakens plans, makes them far more prone to disease, insect attacks and fires. One peer-reviewed vegetation model prepared for the forthcoming U.S. National Assessment shows a short-term "greening" of the southeastern quadrant of the U.S. -- followed by a "browning" in which most of the forests die off and are replaced by grasslands and savannas. Moreover, while heat and carbon increases may temporarily promote plant growth in the north, researchers have found that it will cause huge crop failures in the tropical regions -- e.g., falling rice yields in Southeast Asia, declines in wheat yields in India -- where food crops are growing at the optimum mix of heat and humidity. The research cited by Exxon-Mobil also ignores the fact that as the temperature rises, it will trigger a dramatic growth in the population of crop-destroying and disease-spreading insects -- which will negatively impact plant growth at all latitudes.