The Uncertainty of Warming Estimates

The Nature Reports: Climate Change website recently alerted readers to an oddity in the report of the United Nations Intergovernmental Panel on Climate Change. The IPCC is the source of the "consensus" on global warming/climate change that is often reported in the media.

At issue is something fundamental to any future planning we might do to deal with climate change. To make a long story short, Nature Reports, in the article "Quantifying Climate Change: Too Rosy a Picture?", suggest that the "consensus" conclusion doesn't take into account how uncertain science is about the factors that might warm or cool the planet.

The IPCC published this graph in 2001, showing how human activity is responsible for both warming and cooling effects on climate:




To start, notice that the chart is divided into pink and blue parts. The pink area is for warming effects, and the blue area is for cooling effects. On the left hand side we find carbon dioxide (CO2) and methane (CH4), which are often blamed for global warming. Human activity also produces ozone, which is a cooling effect in the stratosphere (upper atmosphere), but causes warming in the troposphere (the lower atmosphere).




So ozone, carbon dioxide, and methane, plus a few other pollutants, are responsible for some warming of the planet, according to this graph published by the IPCC. There is a little bit of cooling from stratospheric ozone, but not enough to offset the warming from low-altitude ozone, CO2, methane, and other gases. Next time, we'll look at cooling effects, and also begin to note some of the uncertainty of the science. Even the "consensus" report of the IPCC admits the science is uncertain.

The Journal Science Waffles on Warming

In the American Thinker, James Lewis comments on a News-of-the-Week feature in Science, the official journal of the American Association for the Advancement of Science.

The Science news item, Another Global Warming Icon Comes Under Attack, notes that "mainstream atmospheric scientists" are disputing the reliability of the computer models used to predict future warming, and " researchers are giving some ground."

The Intergovernmental Panel on Climate Change, a United Nations committee, has produced a series of reports that have become a Holy Bible of sorts for the global warming alarmists. The reports contain an analysis of current computer global climate models.

The latest IPCC report averaged the results of 14 different computer models and compared the numbers to actual temperature readings throughout the last century. While there is a fair match between actual temperatures and some of the computer predictions, there are uncertainties factor unaccounted for in the IPCC's analysis.

Science's James Kerr writes, "Greenhouse gas changes are well known... but not so the counteracting cooling of pollutant hazes, called aerosols. Aerosols cool the planet by reflecting away sunlight and increasing the reflectivity of clouds. Somehow... modelers failed to draw on all the uncertainty inherent in aerosols so that the 20th-century simulations look more certain than they should."

Bottom line: Aerosols cool the earth. It is uncertain exactly how much they cool the earth. Climate models make predictions which are used to scare the public about global warming. However, the models do not account for the large uncertainty in the amount of cooling from aerosols, including clouds.

The warming effects of greenhouse gases are said to be well-understood and are widely reported. The cooling effects of aerosols are poorly understood, hardly ever reported, and this is not fully explained in the United Nations' official IPCC reports on climate change. What is wrong with this picture?

How can we make rational decisions about public policy when one of the major factors affecting global cooling is not well-understood and not properly taken into account in predictions of climate warming? The answer, obviously, is that we can't.

This new analysis is extremely important, and will be dealt with in one or more future installments on the Global Warming Swindle blog.

NOTE: What are aerosols? "Aerosols are tiny particles suspended in the air. Some occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels and the alteration of natural surface cover, also generate aerosols." (from http://earthobservatory.nasa.gov/Library/Aerosols) Aerosols play an important part in cloud formation. Clouds exert a cooling effect by reflecting solar radiation back into space.

Man can produce greenhouse gases which warm the planet, and he also produces aerosols which lead to cooling. However, in both cases, man's contributions are less a factor in earth's temperature than nature itself, especially solar activity.

Unwarranted emphasis on CO2

If you listen to global warming alarmists for very long, you will get tired of hearing about carbon dioxide, CO2.

To put things into perspective, let us take as fact the speculation of the scientists at realclimate.org who are promoting the theory of man-made global warming.

In comment #17 of this page ("The lag between temperature and CO2"), we learn that Hansen, a NASA scientist who has been much in the news, has estimated that all the greenhouse gases put together account for 35-55% of total warming of earth's climate. CO2 is "roughly half of the total greenhouse gas change," so that brings the figure down to 17-27% of the warming.

The CO2 produced by man's activities is a fraction of the natural CO2 produced by the planet. It is hard to estimate the real impact of man-made CO2 in the atmosphere, but even using the calculations of global warming alarmists, man's contribution to global warming through CO2 is a fraction of the 17-27% already noted.

Obviously CO2 is a greenhouse gas -- it helps the atmosphere trap heat from the sun. But man's contribution to CO2 levels, even if all of the rise from the historic norm (say, 280 parts per million in the year 1000 AD up to the current level of 380 parts per million) was caused by man, is about one fourth of the total.

Man is responsible for 25% of the CO2 in the atmosphere. The CO2 in the atmosphere accounts for 17-27% of the warming, according to the most famous NASA climate scientist. Man's contribution to global warming through CO2 emissions is therefore between 4% and 9% (i.e. 25% of 17-27%).

On Breitbart.com, July 5, an AFP story, "Oldest DNA ever recovered shows warmer planet," details the results of boring 2 kilometers down into a Greenland glacier to discover much warmer temperatures in the past than had been expected. The DNA of ancient plants and animals indicated a "lush forest" environment. In Greenland!

DNA of trees, plants and insects including

butterflies and spiders from
beneath the southern Greenland glacier was

estimated to date to 450,000 to
900,000 years ago, according to the remnants

retrieved from this long-vanished
boreal forest.

The article also points out that temperatures were on average 9 degrees Fahrenheit higher than today during the period between ice ages 116,000 - 130,000 years ago.

Another paper from the premier journal Science, reports that ice cores from Antarctica, providing a record of greenhouse gases in the atmosphere going back 800,000 years, show a variation of 27 degrees Fahrenheit over this time span. In the previous ice age, temperatures were 18 degrees colder than today. At other times, temperatures have been up to 9 degrees higher.

Global warming alarmists are worried about a 1º F temperature rise over the past 100 years. Given that temperatures have historically sometimes been much higher, and at other times much lower on the earth, is it time to panic about a one degree rise?

Climate change is a real phenomenon. Climate is always changing. The ice cores in Greenland and Antarctica prove this. Change is in the nature of climate, even in times when humans did not even exist, let alone burn any fossil fuels.

Religion versus science

This blog will compare the claims of global warming alarmists, especially those who blame the changes in climate on human activity, with scientific research.

Humans affect nature. At question is the type and the degree of the effect.

First, is the earth warming? If so, where? how much has it warmed? how fast is it warming?

Second, if the earth is warming, what might be the most likely causes of that warming? If humans are responsible for part of the warming, how much? 10%? 50%? 80%?

If humans are responsible, or even if they are not, can the warming be stopped? Should it be stopped? Are there benefits to a warmer earth? Would it be less expensive to adapt to climate change than to attempt to stop it?

All these are scientific questions. Some have claimed that the "debate is over" on climate change and global warming. We have caused it by burning fossil fuels and releasing CO2 into the atmosphere, they say. Yet scientists are encountering more and more evidence that does not fit this interpretation of global warming. Are we to ignore the new evidence?

A scientific explanation should be subject to revision as new facts come to light. If proponents of a particular theory cannot change or modify their position in the light of new information, we are dealing not with science, but faith. For some, human-caused global warming has become nearly a religion.

We reject this view. Facts are stubborn things. And many facts stubbornly refuse to fit with the explanations of global warming alarmists. Yet, perhaps they are right. Perhaps humans are causing the earth to warm. We must know for certain before we act, or we may be wasting precious resources. We might even unintentionally make the problem worse!

As future entries to The Global Warming Swindle will demonstrate, the debate is decidedly not over!