By:
John (Mike) Wallace
University of Washington
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Abstract
In variables such as global mean temperature the signal of human-induced climate change stands out clearly above internal variability of the climate system that we refer to as "natural variability". However, when we consider climate change over a limited region such as Texas, the presence of natural variability makes it difficult to see the human-induced signal clearly over the time span of a human lifetime.
The one notable exception is the tropics, where the internal variability is very small and humans and ecosystems have adapted to living within a very narrow temperature range. The difficulty of detecting climate change is compounded when the focus is on short-lived extreme events such as heat waves. To appreciate the gravity of the current global environmental crisis one needs to look beyond climate change. The current California drought provides an example.