David Whitehouse: Has global warming stopped?

'The fact is that the global temperature of 2007 is statistically the same as 2006 and every year since 2001'

Global warming stopped? Surely not. What heresy is this? Haven’t we been told that the science of global warming is settled beyond doubt and that all that’s left to the so-called sceptics is the odd errant glacier that refuses to melt?

Aren’t we told that if we don’t act now rising temperatures will render most of the surface of the Earth uninhabitable within our lifetimes? But as we digest these apocalyptic comments, read the recent IPCC’s Synthesis report that says climate change could become irreversible. Witness the drama at Bali as news emerges that something is not quite right in the global warming camp.

With only few days remaining in 2007, the indications are the global temperature for this year is the same as that for 2006 – there has been no warming over the 12 months.

The fact is that the global temperature of 2007 is statistically the same as 2006 as well as every year since 2001. Global warming has, temporarily or permanently, ceased. Temperatures across the world are not increasing as they should according to the fundamental theory behind global warming – the greenhouse effect. Something else is happening and it is vital that we find out what or else we may spend hundreds of billions of pounds needlessly.

In principle the greenhouse effect is simple. Gases like carbon dioxide present in the atmosphere absorb outgoing infrared radiation from the earth’s surface causing some heat to be retained.

Consequently an increase in the atmospheric concentration of greenhouse gases from human activities such as burning fossil fuels leads to an enhanced greenhouse effect. Thus the world warms, the climate changes and we are in trouble.

The evidence for this hypothesis is the well established physics of the greenhouse effect itself and the correlation of increasing global carbon dioxide concentration with rising global temperature. Carbon dioxide is clearly increasing in the Earth’s atmosphere. It’s a straight line upward. It is currently about 390 parts per million. Pre-industrial levels were about 285 ppm. Since 1960 when accurate annual measurements became more reliable it has increased steadily from about 315 ppm. If the greenhouse effect is working as we think then the Earth’s temperature will rise as the carbon dioxide levels increase.

But here it starts getting messy and, perhaps, a little inconvenient for some. Looking at the global temperatures as used by the US National Oceanic and Atmospheric Administration, the UK’s Met Office and the IPCC (and indeed Al Gore) it’s apparent that there has been a sharp rise since about 1980.

The period 1980-98 was one of rapid warming – a temperature increase of about 0.5 degrees C (CO2 rose from 340ppm to 370ppm). But since then the global temperature has been flat (whilst the CO2 has relentlessly risen from 370ppm to 380ppm). This means that the global temperature today is about 0.3 deg less than it would have been had the rapid increase continued.

For the past decade the world has not warmed. Global warming has stopped. It’s not a viewpoint or a sceptic’s inaccuracy. It’s an observational fact. Clearly the world of the past 30 years is warmer than the previous decades and there is abundant evidence (in the northern hemisphere at least) that the world is responding to those elevated temperatures. But the evidence shows that global warming as such has ceased.

The explanation for the standstill has been attributed to aerosols in the atmosphere produced as a by-product of greenhouse gas emission and volcanic activity. They would have the effect of reflecting some of the incidental sunlight into space thereby reducing the greenhouse effect. Such an explanation was proposed to account for the global cooling observed between 1940 and 1978.

But things cannot be that simple. The fact that the global temperature has remained unchanged for a decade requires that the quantity of reflecting aerosols dumped put in our atmosphere must be increasing year on year at precisely the exact rate needed to offset the accumulating carbon dioxide that wants to drive the temperature higher. This precise balance seems highly unlikely. Other explanations have been proposed such as the ocean cooling effect of the Interdecadal Pacific Oscillation or the Atlantic Multidecadal Oscillation.

But they are also difficult to adjust so that they exactly compensate for the increasing upward temperature drag of rising CO2. So we are led to the conclusion that either the hypothesis of carbon dioxide induced global warming holds but its effects are being modified in what seems to be an improbable though not impossible way, or, and this really is heresy according to some, the working hypothesis does not stand the test of data.

It was a pity that the delegates at Bali didn’t discuss this or that the recent IPCC Synthesis report did not look in more detail at this recent warming standstill. Had it not occurred, or if the flatlining of temperature had occurred just five years earlier we would have no talk of global warming and perhaps, as happened in the 1970’s, we would fear a new Ice Age! Scientists and politicians talk of future projected temperature increases. But if the world has stopped warming what use these projections then?

Some media commentators say that the science of global warming is now beyond doubt and those who advocate alternative approaches or indeed modifications to the carbon dioxide greenhouse warming effect had lost the scientific argument. Not so.

Certainly the working hypothesis of CO2 induced global warming is a good one that stands on good physical principles but let us not pretend our understanding extends too far or that the working hypothesis is a sufficient explanation for what is going on.

I have heard it said, by scientists, journalists and politicians, that the time for argument is over and that further scientific debate only causes delay in action. But the wish to know exactly what is going on is independent of politics and scientists must never bend their desire for knowledge to any political cause, however noble.

The science is fascinating, the ramifications profound, but we are fools if we think we have a sufficient understanding of such a complicated system as the Earth’s atmosphere’s interaction with sunlight to decide. We know far less than many think we do or would like you to think we do. We must explain why global warming has stopped.

Newsweek Magazine, April 28th 1975:

There are ominous signs that the Earth's weather patterns have begun to change dramatically and that these changes may portend a drastic decline in food production - with serious political implications for just about every nation on Earth. The drop in food output could begin quite soon, perhaps only 10 years from now. The regions destined to feel its impact are the great wheat-producing lands of Canada and the U.S.S.R. in the North, along with a number of marginally self-sufficient tropical areas - parts of India, Pakistan, Bangladesh, Indochina and Indonesia - where the growing season is dependent upon the rains brought by the monsoon.
The evidence in support of these predictions has now begun to accumulate so massively that meteorologists are hard-pressed to keep up with it. In England, farmers have seen their growing season decline by about two weeks since 1950, with a resultant overall loss in grain production estimated at up to 100,000 tons annually. During the same time, the average temperature around the equator has risen by a fraction of a degree - a fraction that in some areas can mean drought and desolation. Last April, in the most devastating outbreak of tornadoes ever recorded, 148 twisters killed more than 300 people and caused half a billion dollars’ worth of damage in 13 U.S. states.
To scientists, these seemingly disparate incidents represent the advance signs of fundamental changes in the world's weather. The central fact is that after three quarters of a century of extraordinarily mild conditions, the earth's climate seems to be cooling down. Meteorologists disagree about the cause and extent of the cooling trend, as well as over its specific impact on local weather conditions. But they are almost unanimous in the view that the trend will reduce agricultural productivity for the rest of the century. If the climatic change is as profound as some of the pessimists fear, the resulting famines could be catastrophic. "A major climatic change would force economic and social adjustments on a worldwide scale," warns a recent report by the National Academy of Sciences, "because the global patterns of food production and population that have evolved are implicitly dependent on the climate of the present century."
A survey completed last year by Dr. Murray Mitchell of the National Oceanic and Atmospheric Administration reveals a drop of half a degree in average ground temperatures in the Northern Hemisphere between 1945 and 1968. According to George Kukla of Columbia University, satellite photos indicated a sudden, large increase in Northern Hemisphere snow cover in the winter of 1971-72. And a study released last month by two NOAA scientists notes that the amount of sunshine reaching the ground in the continental U.S. diminished by 1.3% between 1964 and 1972.

Time Magazine June 1974:

In Africa, drought continues for the sixth consecutive year, adding terribly to the toll of famine victims. During 1972 record rains in parts of the U.S., Pakistan and Japan caused some of the worst flooding in centuries. In Canada's wheat belt, a particularly chilly and rainy spring has delayed planting and may well bring a disappointingly small harvest. Rainy Britain, on the other hand, has suffered from uncharacteristic dry spells the past few springs. A series of unusually cold winters has gripped the American Far West, while New England and northern Europe have recently experienced the mildest winters within anyone's recollection.
As they review the bizarre and unpredictable weather pattern of the past several years, a growing number of scientists are beginning to suspect that many seemingly contradictory meteorological fluctuations are actually part of a global climatic upheaval. However widely the weather varies from place to place and time to time, when meteorologists take an average of temperatures around the globe they find that the atmosphere has been growing gradually cooler for the past three decades. The trend shows no indication of reversing. Climatological Cassandras are becoming increasingly apprehensive, for the weather aberrations they are studying may be the harbinger of another ice age.
Telltale signs are everywhere —from the unexpected persistence and thickness of pack ice in the waters around Iceland to the southward migration of a warmth-loving creature like the armadillo from the Midwest.Since the 1940s the mean global temperature has dropped about 2.7° F. Although that figure is at best an estimate, it is supported by other convincing data. When Climatologist George J. Kukla of Columbia University's Lamont-Doherty Geological Observatory and his wife Helena analyzed satellite weather data for the Northern Hemisphere, they found that the area of the ice and snow cover had suddenly increased by 12% in 1971 and the increase has persisted ever since. Areas of Baffin Island in the Canadian Arctic, for example, were once totally free of any snow in summer; now they are covered year round.
Scientists have found other indications of global cooling. For one thing there has been a noticeable expansion of the great belt of dry, high-altitude polar winds —the so-called circumpolar vortex—that sweep from west to east around the top and bottom of the world. Indeed it is the widening of this cap of cold air that is the immediate cause of Africa's drought. By blocking moisture-bearing equatorial winds and preventing them from bringing rainfall to the parched sub-Sahara region, as well as other drought-ridden areas stretching all the way from Central America to the Middle East and India, the polar winds have in effect caused the Sahara and other deserts to reach farther to the south. Paradoxically, the same vortex has created quite different weather quirks in the U.S. and other temperate zones. As the winds swirl around the globe, their southerly portions undulate like the bottom of a skirt. Cold air is pulled down across the Western U.S. and warm air is swept up to the Northeast. The collision of air masses of widely differing temperatures and humidity can create violent storms—the Midwest's recent rash of disastrous tornadoes, for example.

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