Sea lions leave Galapagos because of climate change?

Today we are enlightened by the BBC and its popular story of the poor, innocent sea lions, which are “endemic” to the famous Galapagos Islands in the Eastern Pacific Ocean, who have been driven out of their apparently pristine and untouched paradise by the evil clutches of climate change/global warming/global climate change/whatever the phrase now is (I’ve long given up trying to keep track). They have neglected to mention the possible other, and far more likely reasons, that the sea lions left and the increase in water temperature.

Now I’m not sure if our friends over at the BBC have heard of this natural phenomenon: El Niño. To put it simply: “…the term El Niño refers to the extensive warming of the central and eastern Pacific that leads to a major shift in weather patterns across the Pacific” (Bureau of Meteorology; 2010, http://www.bom.gov.au/climate/glossary/elnino.shtml). This is, in very basic terms, the movement of huge masses of water throughout the Central Pacific Ocean which are at different temperatures. This causes less rainfall on the eastern side and more rainfall on the western side, due to warmer ocean temperatures, weaker than normal eastern trade winds and a low SOI (Southern Oscillation Index). El Niño also has a ‘partner in crime’: La Nina, which causes the same effects, except in reverse.

What does this have to do with sea lions leaving the Galapagos Islands? Well, it has quite a bit to do with it. As you can see in Figure 1, El Nino can change the water temperature dramatically.

Figure 1

http://sealevel2.jpl.nasa.gov/jr_oceanographer/oceanographer-perigaud.html

However, even El Nino can’t account for all of the temperature rise. The temperature rise quoted by this Peruvian Organisation (Organisation for Research and Conservation of Aquatic Animals) was 5C – from 17C to 23C over the last 10 years. This is interesting, because it’s not backed up by pretty much the only raw data available from the immediate area.

Figure 2 is from Nonura, Peru, close by to where the organisation’s temperature monitor is. It’s a graph documenting sea temperatures from 1984-2005, using oceanographic satellite measurements of nearby open water.

Figure 2

http://www.surf-forecast.com/breaks/Nonura/seatemp

It is interesting to note that the 23C cited by the ORCAA is actually lower that the average temperature from 1981-2005, which was 24C.

It is also interesting to note the following information from the aforementioned website:

“Actual water temperatures close to shore at Nonura can vary by several degrees compared with these open water averages. This is especially true after heavy rain, close to river mouths or after long periods of strong offshore winds. Offshore winds cause colder deep water to replace surface water that has been warmed by the sun.”

Thus, it would appear that the temperature rise quoted by the organisation may, in fact, not be due to climate change, but to a number of perfectly normal phenomena.

UPDATE: It would appear that even the BBC have realised the fallacy of this connection. The day after the article was posted (and when I halfway through this rant), they posted a “correction” on the end of the page, correcting three major mistakes that they had made in the story. It would appear that even the otherwise mostly reputable BBC has no hesitation in rushing alarmist stories to the publishing stage before properly checking the facts.

http://news.bbc.co.uk/2/hi/americas/8503397.stm

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