This is complicated, so I’m going to break it down. I’ll send out a series of FAQs on this. Stick with me for a minute. There are a couple of concepts you need to know then you can take a break.
First, climate change is not weather. It is not a single Category 5 hurricane or even a season of them. It is not an unusually warm day in the winter or a cold day in the summer. No one, not the most ardent proponent of climate change or the most antagonistic detractor can point to a weather event or string of weather events and say, “Aha! This proves it!”
Climate refers to a long-term average of weather, the typical average for climate purposes is over thirty years. Climate can also be viewed over thousands of years (e.g. an ice-age). If you have a decade of unusual weather, that is not climate or climate change. That is weather. Two back-to-back 500-year storms is weather. A warm winter is weather. A rainy summer is weather. Thirty or so years of 500-year storms, warmer than average winters, or dry weather, now you’re talking climate.
Climate change, in its commonly-understood sense, is change to climate that is caused by human-induced causes (called anthropogenic by climate nerds). It can also be caused by totally natural occurrences, such as sunspots, volcanic activity, wobbles in the earth’s rotation, etc. Determining the cause of climate change is the work of thousands of scientists from a variety of scientific fields. No single scientific discipline can lay claim to being the sole experts.
Here’s another thing to keep in mind. The study of climate change is devilishly complicated. The scientists who study climate change are (mostly) PhDs in climatology, meteorology, geology, biology, botany, paleontology, glaciology, physical geography, statistics, and a host of other learned professions. I try to follow their work.
When it comes to scientific issues, I DO NOT FOLLOW OR LISTEN TO radio talk show hosts, former vice-presidents, actors, journalists, documentary filmmakers, or activists on either side. They are cheerleaders, maybe explainers, not scientists. At best, these folks can advocate for one side or the other, but not from a scientific perspective. My degrees are in geography (B.S.) and law. Now I am a novelist. I am not a scientist. You can stop listening to me now.
Here are three definitions that should help:
Climate change is defined as: “A change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings such as modulations of the solar cycles, volcanic eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land use.” Intergovernmental Panel on Climate Change, 2013: Annex III: Glossary [Planton, S. (ed.)]. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, at p. 1450. (“IPCC definition”).
That is not the only definition of climate change. Here is another: “Note that the Framework Convention on Climate Change (UNFCCC), in its Article 1, defines climate change as: ‘a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods’. The UNFCCC thus makes a distinction between climate change attributable to human activities altering the atmospheric composition, and climate variability attributable to natural causes.” IPCC definition, quoting Art. 1, Framework Convention on Climate Change (UNFCCC).
Climate is: “In a narrow sense is usually defined as the
average weather, or more rigorously, as the statistical description in
terms of the mean and variability of relevant quantities over a period of time
ranging from months to thousands or millions of years. The classical period for
averaging these variables is 30 years, as defined by the World Meteorological
Organization. The relevant quantities are most often surface variables such as
temperature, precipitation and wind. Climate in a wider sense is the state,
including a statistical description, of the climate system. IPCC definition at
That’s enough for now. Here are a few takeaways.
• Climate is not weather.
• Climate is an average of weather over 30 years or more.
• Climate change may be attributed to natural or human-caused (anthropogenic) reasons.
• Talk show hosts, actors, and novelists are not climate scientists.
In coming FAQs, I’ll talk about why the vast majority of scientists who study climate change believe that the climate is being changed by man.