Climate change is part of cycle

The following updates some of the topics referred to in a letter to the editor entitled “Columnist shuns reality of climate change” (Dec.7).

The following updates some of the topics referred to in a letter to the editor entitled “Columnist shuns reality of climate change” (Trail Daily Times Dec. 7).

According to testimony given in the UK by Professor Phil Jones in connection with the Climategate scandal, global warming stopped in 1995. This testimony is supported by both satellite and ground measurements and is consistent with historical decadal climate cycles (www.droyspencer.com/latest-global-temperatures).

The warming referred to by Jos Sharp began in the 1970s and was preceded by a cooling cycle that started in the early 1940s. The current cooling cycle started in 2002.

These decadal cycles are superimposed on a warming trend, which represents a recovery from the severe stages (1645 to 1715) of the Little Ice Age. The warming trend forms what is known as the Modern Warm Period, the coolest of the six warm periods since the last glaciation 10,000 years ago.

According to satellite measurements, the current rates of sea level rise are well within natural variability and well below the  maximum rates of the post-glacial period.

However, the most recent measurements suggest a static/decreasing level (http://sealevel.colorado.edu).

The satellite sea level trend is consistent with the trend measured by 23 marine gauges over a 125-year period. Furthermore, observations at various islands and seaports reveal that the sea level rise has approximately leveled off in the last few thousand years. Two pertinent graphs (“Recent Sea Level Rise” & “Post-Glacial Sea Level Rise”) can be found at http://rst.gsfc.nasa.gov/Sect16/Sect16_2.html.

In a Geophysical Research Letter (AGU June 2011), Dr. Ryan N. Maue reports that the tropical cyclone energy has “decreased dramatically to the lowest levels since the late 1970s” and that “the frequency of tropical cyclones has reached a historical low (http://policlimate.com/tropical/index.html).”

However, I suggest that this trend may reverse itself if we have passed the peak of the Modern Warm Period. The greater thermal gradients of another “Little Ice Age” will increase the strength and frequency of hurricanes, all in accordance with basic thermodynamic principles.

The foregoing, together with the information provided in my letter (Trail Daily Times, Nov. 29, 2011) make it abundantly clear that, unfortunately, we are unable to control the planet’s climate with our carbon dioxide emissions.

Climate is always changing and it has been much warmer and much colder.

Thorpe Watson, PhD

Warfield