Taking the earth's temperature and the influence of ocean sea surface temperature cycles

I had a go at charting the global mean temperature trend. An interesting thing to do as it gives you an insight into all those global mean temperature graphs you see.

I started off with the GISS temperature anomaly dataset that goes from 1880 up to the present. The temperature anomaly data is provided in monthly intervals based upon a 1951-1980 baseline of 14.0 deg-C, but I really only used the data from 1970 to the present.

Using monthly data you see the extremes that sometimes occurr, both on the warm side and the cold side. I added a 12 month running average trend line (red) and a 5 year running average trendline (dark blue) to make the temperature trend clearer.

Here is the result:

Development of El Niño in 2014

The El Niño Southern Oscillation (ENSO) is one of the important cycles affecting global weather, particularly around the Pacific region, but also having indirect impacts on a global level. Changes to winds and precipitation causing floods and droughts depending upon the region. El Niño also results in increasing global average temperatures, on top of the long term trend associated with climate change.

Cost estimates in US$ for 1982-1983 El Niño
Extreme Event / Country	Cost in $millions
Flooding
Bolivia	$300
Ecuador, Northern Peru	$650
Cuba	$170
U.S. Gulf States	$1,270
Hurricanes
Tahiti	$50
Hawaii	$230
Droughts/Fires
Southern Africa	$1,000
Southern India, Sri Lanka	$150
Philippines	$450
Indonesia	$500
Australia	$2,500
Southern Peru, Western Bolivia	$240
Mexica, Central America	$600
Total Costs	$8,110 million
Source: NASA via University of California San Diego

The El Niño cycle is usually 3 to 7 years. And occasionally we'll get an extreme response, a super El Niño. The 1982-83 and 1997-1998 produced super El Niños spiked global temperatures to record levels, causing floods, drought and increasing bushfire conditions. The back to back La Nina of 2010 and 2011 was also quite strong producing Australia's wettest two year period on record and reducing global sea level by 5mm.

he 1982-1983 event has been estimated to have caused about $8.1 billion in damages and was largely unexpected without the warning and forecasting systems we have in place today.

The last Super El Niño event in 1997-1998 resulted in about 23,000 people killed as a result of ENSO linked extreme weather events and caused about $45-50 billion in losses to global agricultural output according to a Canberra Times report.

Predicting El Niño events and issuing alerts allows communities to prepare for the worst. It is essential for farmers to know the forecast for rain or drought so that crop plantings can be varied and livestock rates altered to minimise losses.

Guest Post: Atmospheric surface warming stalled by strong Trade winds driving heat into Pacific ocean

By Michael Hopkin, The Conversation, who interviewed Steve Rintoul from CSIRO, Richard Allan Professor of Climate Science at University of Reading, and Mathew England a Climatologist at University of New South Wales.

The “pause” in global warming since 2001 can be explained by the discovery of unusually strong winds in the Pacific, climatologists have found.

Global surface air temperatures have more or less flatlined since the turn of the century, prompting some observers to claim that the planetary warming trend has stopped. But the new research, published in Nature Climate Change, shows how stronger winds have driven the excess heat down into the ocean.

Researchers led by Matthew England, a professor of climatology at the University of New South Wales, began by looking at the differences between the 1990s, when Earth’s surface was strongly warming, and the 2000s, after the hiatus began.

Previous research has already shown that cooler temperatures over the eastern Pacific are linked to a slowdown in worldwide warming, but researchers wanted to know why.

Warming may spike when Pacific Decadal Oscillation moves to a positive phase

We are currently in a negative phase of the Pacific Decadal Oscillation, a cycle with phases that can last between 15 to 30 years. During a negative phase waters are cooler and heat mixes into deeper levels of the north Pacific ocean. When the next phase change ocurrs to a positive PDO we are likely to see some of the stored ocean heat released spiking atmospheric temperatures.

The Pacific Decadal oscillation was only identified by scientists in the 1990s, and we only have accurate observational data for identifying it going back some 50-60 years. Nathan J Mantua and SR Hare from the University of Washington in Seattle described the operation of the Pacific Decadal Oscillation in the Journal of Oceanography in 2002 (Mantua & Hare 2002 PDF). Read more about the PDO from the Climate Impacts Group from University of Washington.