A Guide to Understanding Global Temperature Data by Roy W. Spencer, Ph.D.

INTRODUCTION

 

When we measure temperature in our backyard, we really aren’t that concerned if the thermometer we use is off by a degree or two. Since most people live where the temperature fluctuates by many degrees every day, and the seasonal swing in temperatures can be 80 F or more, a couple of degrees doesn’t matter too much.
But in the case of global warming, one or two degrees is the entire change scientists are trying to measure over a period of 50 to 100 years. Since none of our temperature monitoring systems was designed to measure such a small change over such a long period of time, there is much disagreement over exactly how much warming has or will occur.
Whether we use thermometers, weather balloons, or Earth-orbiting satellites, the measurements must be adjusted for known sources of error. This is difficult if not impossible to do accurately. As a result, different scientists come up with different global warming trends—or no warming trend at all.
So, it should come as no surprise that the science of global warming is not quite as certain as the media and politicians make it out to be.
Increasingly, the “science” of global warming is being based upon theories of what might happen, not on what is being observed to happen. And the observations are increasingly at odds with the theory. The United Nations Intergovernmental Panel on Climate Change (IPCC) relies upon theoretical climate models which predict about 2 C (3.8 F) of warming by the end of this century, due primarily to carbon dioxide emissions resulting from our burning of fossil fuels. The IPCC claims that this rate of warming could be catastrophic for some forms of life.
But is the Earth really warming as rapidly as the IPCC says? And, is that warming entirely the fault of humans?
In this paper I will answer some basic questions about global temperature data in particular, climate change in general, and what it all means for the debate over energy policy. The following questions are some of the more frequently ones asked of me over the last 20 years I have been performing climate change research under U.S. government funding.
These questions include:
1) Does an increasing CO2 level mean there will be higher global temperatures?
2) Can global temperatures go up naturally, even without rising CO2 levels?
3) How are temperature data adjusted?
4) Are global temperatures really going up? If so, by how much?
5) Is warming enough to be concerned about? Is warming necessarily a bad thing?
6) Could the warming be both natural and human-caused?
7) Why would the climate models produce too much warming?
8) What is climate sensitivity?
9) Don’t 97 percent of climate researchers agree that global warming is a serious
man-made problem?
10) Haven’t ocean temperatures been going up, too?
11) What does it mean when we hear “the highest temperature on record”?
12) Is there a difference between weather and climate?
13) Why would climate science be biased? Isn’t global warming research
immune from politics?
From the answers to these questions that follow it should be clear that the science of global warming is far from settled.
Uncertainties in the adjustments to our global temperature datasets, the small amount of warming those datasets have measured compared to what climate models expect, and uncertainties over the possible role of Mother Nature in recent warming, all combine to make climate change beliefs as much faith-based as science-based.
Until climate science is funded independent of desired energy policy outcomes, we can continue to expect climate research results to be heavily biased in the direction of catastrophic outcomes.