Climate Change & Renewables - 6:Pause Cause

(Click on graphic images to enlarge)

Why has there been an apparent pause in the increase in average temperatures since 1998?  Several reasons - some of which are covered in the NYT article here:

http://www.nytimes.com/2014/05/20/upshot/how-el-nino-might-alter-the-political-climate.html?ref=natecohn

Two key points from that article are that choosing 1998 as a starting point is misleading because 1998 saw a big spike in global temperatures from 1997.  With all the natural variability it would be unlikely to see such a big temperature spike as occurred in 1997-1998 followed by further big increases.  Starting measuring from just a few years earlier shows the temperature trend is up. 

You can see an earlier pause in the global temperature rise due to "Global Dimming" during 1950-1970 (see below) in the following video.  A 26 second long video animation of the temperature changes year-by-year from 1889 to 2013 is here (opens in new window):
http://svs.gsfc.nasa.gov/vis/a000000/a004100/a004135/GCM2013update_robinsonComposite.mp4

There is a decade long oscillation between "El Nino" and "La Nina" weather patterns.  From the above NYT article: "In this chain of events, a strong El Niño causes a shift in a longer cycle known as the Pacific Decadal Oscillation, which favors more frequent and intense El Niños during its “warm” or “positive” phase. The oscillation has been “negative” or “cool” since the historic El Niño of 1998."

Fishermen on Nearly Dried-Up El Negro River in Brazil Blamed on El Nino

The main point of the NYT article is that La Nina and El Nino conditions affect the entire globe, not just California, causing droughts in parts of the world at the same time they cause flooding in other parts.  They also cause changes in temperature. A "La Nina" may have put a temporary pause in the upward trend.  An "El Nino" seems to be forming now and if it is a strong one, CA will replace its drought with flooding, and the pause in global warming will end.  Of more concern than the pause in increase ought to be that the options seem to be "warmer or not warmer" when they would be "warmer or cooler" if there were no warming trend.

Another factor is "Global Dimming" which occurs because aerosols in the air from volcanic activity, burning coal, slash-and-burn agriculture, etc. act like an umbrella to block the sun and cool the earth.  The post WW-II economic boom resulted in a steady increase in these emissions resulting in a cooling effect from 1940 to 1970.  The peak (measured in sulfur emissions) was in 1970.  The effects of these emissions were acid rain and other very obvious harmful effects on agriculture, material, and people so action was taken very quickly to eliminate aerosols.  As a result, soot and sulfur emissions have declined dramatically since then.  Aerosol optical thickness is slowly declining with the exception of temporary peaks right after volcanic eruptions.  Aerosols and soot wash out of the atmosphere in weeks or months so if we stop putting more in, it goes away very quickly.  CO2 however stays in the atmosphere quite a while.  Methane, CH4, doesn't last as long but it reacts in air to form CO2 and H2O both of which act as greenhouse gas emissions so its effect outlives its own life.  See a NASA article here:

http://earthobservatory.nasa.gov/Features/GISSTemperature/giss_temperature4.php

Atmospheric Sulfur from 1900 to 2000

From the above NASA report: "climate scientists estimate aerosols may have offset global warming by as much as 50 percent by reducing the amount of sunlight reaching the surface"

Aerosol Optical Thickness - Peaks Show Volcanic Activity

Wikipedia article here:

http://en.wikipedia.org/wiki/Global_dimming

In economics, an externality "is the cost or benefit that affects a party who did not choose to incur that cost or benefit" (from Wikipedia on "Externality").  The effects of pollution and greenhouse gas warming are externalities borne by those who may contribute not at all to it.  

A carbon tax at the pump was proposed recently but looks unlikely to pass as it is opposed by the environmentalists and the governor.

http://www.bloomberg.com/news/2014-02-28/california-carbon-tax-would-be-first-at-the-gas-pump.html

One purpose of a carbon tax is to tax the externality with the hope that people will devise a way to eliminate its effect on those who don't want it and didn't cause it or benefit from it. Eliminating subsidies to fossil fuel extraction companies was agreed at the G20 meeting in 2009 and would do a lot to acheive this. In effect, a subsidy is a tax on everyone to, in this case, add further to global warming.  Eliminating it would cause an increase in the cost of coal and oil and hopefully bring the true costs of fossil fuel to be seen as more expensive than renewable production.  A panel of distinguished economists all seem to agree on that as seen here:

http://marginalrevolution.com/marginalrevolution/2014/03/summers-lomborg-cowen-and-tabarrok-on-climate-change.html 

Personally, I would have greatly preferred that the proceeds from the CA carbon tax be used to convert existing power plants to renewable-based power generation.  Instead, it will go to funding all the little pet projects of the legislators to appease their main campaign contributors.  Still, making pollution and greenhouse gas emissions more expensive will drive a flight to renewables.  The power cos. have been treating the air we breath and the climate we live in as if it were a free resource they could dump into without cost.