Global Warming Explained
Is Earth warming up or not?
But the Earth is warming up, you say. Well, the evidence for that is very skimpy and is, due to the poor quality of surface temperature recordings, not supported by an overwhelming quantity and quality of facts. Moreover, what we can consider to be normal at any given time depends on the time interval into which a given point in time falls.
The climate alarmists do not tell us that for the years following the "high" temperatures reached in 1998 the global average annual temperatures reached were in every single year below the "high" reached in 1998 and appear to have begun a downward trend.
Many surface temperature measurements that are being tracked and reported are being taken and recorded in or near large urban centres. It would be no more accurate to extrapolate from them to the rest of the World than it would be to extrapolate from the reading in my kitchen right now and to conclude that we really and truly don't have now [in 2003] the coldest spring we've had for the last 150 years, ever since temperatures were recorded more or less on a global basis.
And that is where the problem lies. We don't have a sufficiently accurate record of surface-air-temperature readings to tell us what our climate has been in this region, or in North America, or for that matter in the whole World, to tell us what normal is. What we know is that "normal" is the average of a whole range of values. What we don't know is what the whole range of values is and how far away from or how close to normal we are right now, or do we?
Whatever the length of the interval, whether it covers the last 12 thousand, 450 thousand, 5 million, 65 million or 500 million years, global average temperatures have been falling steadily. The annual global average temperatures are now considerably lower than they were many times in the past.