‘Large, abrupt climate changes have affected hemispheric to global regions repeatedly, as shown by numerous paleoclimate records (Broecker, 1995, 1997). Changes of up to 16°C and a factor of 2 in precipitation have occurred in some places in periods as short as decades to years (Alley and Clark, 1999; Lang et al., 1999). However, before the 1990s, the dominant view of past climate change emphasized the slow, gradual swings of the ice ages tied to features of the earth’s orbit over tens of millennia or the 100-million-year changes occurring with continental drift. But unequivocal geologic evidence pieced together over the last few decades shows that climate can change abruptly, and this has forced a reexamination of climate instability and feedback processes (NRC, 1998). Just as occasional floods punctuate the peace of river towns and occasional earthquakes shake usually quiet regions near active faults, abrupt changes punctuate the sweep of climate history.’
‘Recent scientific evidence shows that major and widespread climate changes have occurred with startling speed. For example, roughly half the north Atlantic warming since the last ice age was achieved in only a decade, and it was accompanied by significant climatic changes across most of the globe. Similar events, including local warmings as large as 16°C, occurred repeatedly during the slide into and climb out of the last ice age. Human civilizations arose after those extreme, global ice-age climate jumps. Severe droughts and other regional climate events during the current warm period have shown similar tendencies of abrupt onset and great persistence, often with adverse effects on societies.’ http://www.nap.edu/openbook.php?record_id=10136&page=R1
Well obviously someone is right and someone wrong – the NASA page you link to or the NAS Committee on Abrupt Climate Change consisting of many of the world’s leading climate change researchers.
Odd – I think I provided this link – http://earthobservatory.nasa.gov/IOTD/view.php?id=8703 – and here is the conclusion.
‘Unlike El Niño and La Niña, which may occur every 3 to 7 years and last from 6 to 18 months, the PDO can remain in the same phase for 20 to 30 years. The shift in the PDO can have significant implications for global climate, affecting Pacific and Atlantic hurricane activity, droughts and flooding around the Pacific basin, the productivity of marine ecosystems, and global land temperature patterns. This multi-year Pacific Decadal Oscillation ‘cool’ trend can intensify La Niña or diminish El Niño impacts around the Pacific basin,” said Bill Patzert, an oceanographer and climatologist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The persistence of this large-scale pattern [in 2008] tells us there is much more than an isolated La Niña occurring in the Pacific Ocean.”
Natural, large-scale climate patterns like the PDO and El Niño-La Niña are superimposed on global warming caused by increasing concentrations of greenhouse gases and landscape changes like deforestation. According to Josh Willis, JPL oceanographer and climate scientist, “These natural climate phenomena can sometimes hide global warming caused by human activities. Or they can have the opposite effect of accentuating it.”’
It seems pretty clear that we are in a cool mode. Look for yourself.
http://www.esrl.noaa.gov/psd/enso/mei/
http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/ca-pdo.cfm
La Nina and cool PDO (cool IPO) to 1976/77, El Nino and warm PDO (warm IPO) to 1998, and La Nina and cool PDO since (cool IPO). They say these modes last 20 or 30 years – but it is more like 20 to 40 years in the proxies. This evidence seems pretty obvious to the unbiased observer – aye FOMBS?
So the NASA page you show is wrong on both counts by a long way. Do you think they should take it down rather than mislead more innocents? Or allow people like you to practice to deceive? I think so. It seems written by a Rebecca Lindsay – listed as a technical writer rather than a scientist. It seems that both she – and you – have got it all wrong.
