- Joe Romm: The Really Awful Truth About Climate Cha...
- Why the 97 per cent consensus on climate change st...
- Jeff Masters: extreme, record-breaking temperature...
- When nutcases and idiots are elected to Congress, ...
- Stefan Rahmstorf: What's going on in the North Atl...
- Super El Nino Likely as Huge Warm Water Wave Hits ...
- World headed for an El Nino and it could be a big ...
- ▼ May (7)
- ► 2014 (862)
- ► 2013 (1259)
- ► 2012 (1040)
- ► 2011 (2089)
- ► 2010 (1317)
- ► 2009 (1326)
- ► 2008 (510)
Monday, May 18, 2015
Thursday, May 14, 2015
Illustration by Lisk Feng
In 2004, science historian Naomi Oreskes published a short paper in the journal Science concluding there was an overwhelming consensus in the scientific literature that global warming was caused by humans.
After the paper’s release, there was some unexpectedly hostile reaction. This prompted Oreskes and her colleague Erik Conway to go even deeper with their research, leading to the publication of the book Merchants of Doubt. It documents how a small group of scientists with links to industry were able to sow doubt about the scientific consensus and delay effective policy on DDT, tobacco, acid rain and, now, global warming.
Fast forward to two years ago: a team of volunteer researchers (myself included) associated with the website Skeptical Science decide to update and extend Oreskes’ research. Led by University of Queensland researcher John Cook, we analyzed the abstracts of about 12,000 scientific papers extracted from a large database of articles, using the search terms “global warming” and “global climate change.” The articles had been published over a 21-year period, from 1991 to 2011.
As an independent check on our results, we also sent emails to the more than 8,500 scientist authors of these articles. (These were the scientists whose e-mail addresses we were able to track down). We asked them to rate their own papers for endorsement or rejection of man-made global warming.
Both approaches yielded a very similar result: 97 per cent of the scientific literature that expresses an opinion on climate change endorses the expert consensus view that it is man-made. The results were published in May 2013 in the journal Environmental Research Letters.
We were astonished by the positive reception. Mention of the paper was tweeted by U.S. President Barack Obama, Al Gore and Elon Musk, among others. Obama later referenced it in a speech at the University of Queensland, while U.S. Secretary of State John Kerry has referred to the 97 per cent consensus in recent speeches. John Oliver based an episode of his HBO comedy show Last Week Tonight around it, a clip viewed online more than five million times.
The paper has been also been downloaded over 300,000 times – so far – which makes it a blockbuster for a science paper.
We knew that our paper would be unpopular among climate contrarians, but we were taken aback by the ferocity of the attack and the obsessiveness of some of our critics.
One of the most persistent among them is Professor Richard Tol, an econometrician who teaches at the University of Sussex. Over the past two years, Tol has published numerous blog articles, written letters and submitted Freedom of Information requests to lead author John Cook’s employer, the University of Queensland. Tol has also petitioned the publisher of the article, the Institute of Physics, to have the paper withdrawn.
Expert reviewers at the journal Environmental Research Letters rejected the rebuttal that Tol submitted. After shopping his rebuttal around to other journals, Tol found one, Energy Policy, which agreed topublish his comment. The journal gave us the right to reply, but we didn’t have enough space to do so and we needed a supplementary publication to fully detail the many errors in his analysis.
Tol is no stranger to controversy. He had a vicious public dispute with economist Frank Ackerman, in the course of which he badgered Ackerman’s employer and tried to get Ackerman fired. Eventually, a group of eminent economists published an extraordinary open letter where they upbraided Tol for his unprofessional conduct.
He also wrote a series of letters to the Stockholm Environmental Institute (SEI), which was first to publish the article co-authored by Ackerman. The SEI issued a public statement, which supported Ackerman. “Professor Tol’s repeated, groundless attacks on this article, and on SEI for its association with the article, have violated the norms of civility and scholarly debate,” it said. “We urge Professor Tol to stop attacking the motivations and reputations of others, and to return to the academic community that accepts disagreement and engages in substantive debate.”
More recently, Tol has had some bitter exchanges with Bob Ward, of the London School of Economics, who had pointed out that one of Tol’s published papers contained serious errors. The errors were eventually formally corrected in the original journal (the correction was itself later corrected) and the IPCC had to change its report that had referenced Tol’s paper. The corrections related to a claim by Tol that small amounts of global warming have a beneficial effect, a false result that has been widely promoted by climate contrarians.
What is astonishing about Tol’s campaign is that he does not himself deny the physical science of global warming and also admits that the percentage consensus on man-made climate change is in the high nineties. His criticism consists of a long list of trivial and tendentious comments on methodology, the consequences of which he concedes—either explicitly or by default—have no significant impact on the outcome.
It came as no surprise to anyone working in climate research that there is an overwhelming scientific consensus on human-caused global warming. Our result was consistent with the outcomes of earlier studies that had measured scientific agreement by other means.
There are many areas in climate science that are not settled and that need more research. But mainstream scientists don’t waste their time arguing about whether or not humans are causing climate change. Increasingly, as we found, many scientists no longer even mention the human cause of modern climate change in their papers. It is taken for granted as are, for example, natural selection in the life sciences and plate tectonics in geology.
However, surveys show that the general public is misinformed about the degree of scientific agreement on global warming. People who do not accept human-caused climate change generally believe that a large fraction of scientists disagree with the basic notion of man-made warming. But even among people who accept the scientific consensus, there’s a false belief that there is significant disagreement among the experts.
Some of this difference of opinion can be explained by politics and culture, with conservatives tending to favour a low estimate of the perceived consensus and liberals a higher one. But there remains a gap – independent of politics – between how much the public thinks scientists agree on the fundamentals of climate change and what the actual level of agreement is.
We call this the “consensus gap” and it is that misunderstanding we are trying to correct. Part of that gap is due to people simply not being sufficiently informed, but part of it is because they have been actively misinformed by those seeking to oppose or delay public policy.
Recent social-science research has shown that the acceptance of the existence of the expert consensus on climate change is a gateway belief. If somebody is not aware, or refuses to accept that there is an overwhelming majority of experts who agree that humans have caused global warming, you are unlikely to be able to persuade them about the more uncertain future consequences of climate change. And you certainly won’t be able to persuade them to support policies to reduce emissions.
Convincing people that the experts agree on the fundamentals of the science is not, of course, sufficient to solve the climate problem, but it is a necessary step.
Tol is not the only one who has tried and failed to show our results are flawed. Climate contrarians everywhere protest there is no scientific consensus. If that were true, they should easily be able to show there is indeed a significant body of work that challenges mainstream science. Yet they haven’t and can’t, because a robust and coherent denial of man-made global warming does not exist.
Our study describes the state of expert opinion, it does not define scientific truth nor does it tell people what to think. Climate scientists today overwhelmingly endorse the consensus view that humans are the cause of most of recent global warming. That’s a fact.
If the goal is to sell doubt and delay action on climate, it’s a fact that has to be denied.
All-Time May Heat Record for Europe Falls For the 2nd Time This Monthby Jeff Masters, wunderblog, May 14, 2015
An extreme May heat wave unprecedented in European recorded history has invaded Spain and Portugal, bringing the hottest May temperatures ever recorded on the continent. According to the Spanish meteorological agency, AEMET, at least four stations in the Valencian Community of eastern Spain hit temperatures today in excess of the previous European May heat record set just eight days ago -- a 41.9 °C (107.4 °F) reading at Catenanuova, Sicily (Italy) on May 6. Today's European record-breaking May temperatures in Spain included:
Carcaixent: 42.9 °C (109.2 °F)
Xativa: 42.7 °C (108.9 °F)
Algemesi: 42.6 °C (108.7 °F)
Valencia: 42.6 °C (108.7 °F)
Many stations in Spain's Valencian community went above their June records, and were near their all-time records for any month. The record set at Valencia Airport today was 6.6 °C (11.9 °F) above the previous highest May temperature, was 4.4 °C (7.9 °F) higher than the record for June, and was the 3rd hottest temperature since records began in 1869 for any month! This week's heat wave began yesterday, when hot air from North Africa flowed northwards over Spain and Portugal, setting all-time May heat records at Madrid, Sevilla, Cordoba, Ciudad Real, Granada, and many other cities. Portugal beat its all-time May heat record with a 40.0 °C (104.0 °F) reading at Beja EMA (old record: 39.5 °C, 103.1 °F, at Regua on May 28, 2001). The most remarkable record yesterday, however, was from the Canary Islands to the southwest of Spain, where Lanzarote Airport hit 42.6 °C (108.7 °F), breaking its old record for the entire month of May by 6 °C (10.8 °F)! The old record was 36.6 °C (97.9 °F) on May 24, 1986.
Figure 1. Predicted high temperatures for Thursday, May 14, 2015, for Spain from AEMET. Temperatures of 42.0 °C are hotter than any May readings on record for Spain.
According to weather records researcher Maximiliano Herrera, Europe also had its earliest 40 °C temperature ever recorded this month -- a 40.4 °C (104.7 °F) reading at San Priamo in southeastern Sardinia on May 5. Prior to 2015, the previous all-time hottest May temperature recorded in Europe was 41.7 °C (107.1 °F), on May 17, 2006 in Andujar, Spain. What's really remarkable about the two European all-time May heat records set this month is that they have occurred in the first half of the month. We would expect all-time monthly heat records to fall near the end of the month, as summer's heat begins to really ramp up. Note that the World Meteorological Organization (WMO) does not maintain official monthly all-time extreme temperature records for the continents, so the records quoted here are from Maximiliano Herrera.
Thanks go to Maximiliano Herrera and Michael Theusner for the temperature records provided in this post.
While these damned fool Republicans are busy talking about farts and listening to a quack like John Christy, Spain is experiencing off-the-charts, record-breaking temperatures
On May 13, 2015, the Committee held a hearing on a proposed guidance to federal agencies on implementing the National Environmental Policy Act. Republicans on the Committee spent the hearing denying the science and risks of climate change. These are the highlights.
On May 13, 2015, the Committee held a hearing on a proposed guidance to federal agencies on implementing the National Environmental Policy Act. Republicans on the Committee spent the hearing denying the science and risks of climate change. These are the highlights.
Wednesday, May 13, 2015
by Stefan Rahmstorf, RealClimate, March 23, 2015
The North Atlantic between Newfoundland and Ireland is practically the only region of the world that has defied global warming and even cooled. Last winter there even was the coldest on record – while globally it was the hottest on record. Our recent study (Rahmstorf et al., 2015) attributes this to a weakening of the Gulf Stream System, which is apparently unique in the last thousand years.
The whole world is warming. The whole world? No! A region in the subpolar Atlantic has cooled over the past century – unique in the world for an area with reasonable data coverage (Fig. 1). So what’s so special about this region between Newfoundland and Ireland?
Figure 1. Linear temperature trend from 1900 to 2013. The cooling in the subpolar North Atlantic is remarkable and well documented by numerous measurements – unlike the cold spot in central Africa, which on closer inspection apparently is an artifact of incomplete and inhomogeneous weather station data.
It happens to be just that area for which climate models predict a cooling when the Gulf Stream System weakens (experts speak of the Atlantic meridional overturning circulation or AMOC, as part of the global thermohaline circulation). That this might happen as a result of global warming is discussed in the scientific community since the 1980s – since Wally Broecker’s classical Nature article “Unpleasant surprises in the greenhouse?” Meanwhile evidence is mounting that the long-feared circulation decline is already well underway.
The Atlantic circulation (AMOC) as part of the global overturning circulation of the oceans in an animation from NASA.
Difficult to measure
Climate models have long predicted such a slowdown – both the current 5th and the previous 4th IPCC report call a slowdown in this century “very likely,” which means at least 90% probability. When emissions continue unabated (RCP8.5 scenario), the IPCC expects 12% to 54% decline by 2100 (see also the current probabilistic projections of Schleussner et al., 2014). But the actual past evolution of the flow is difficult to reconstruct owing to the scarcity of direct measurements. Therefore, in our study we use data on sea surface temperatures in order to infer the strength of the flow: we use the temperature difference between the region most strongly influenced by the AMOC and the rest of the Northern Hemisphere.
Figure 2. Schematic of the Atlantic circulation. Surface currents in red, deep currents in blue, sea-ice cover in winter in white. (Source: Rahmstorf, Nature 1997)
Now we are not the first to have inferred from temperature data that the flow must have weakened. Evidence for this was already presented by Dima and Lohmann (2010) or Drijfhout et al. (2012), among others (for further references see the introduction of our paper).
What is new is that we have used proxy reconstructions of large-scale surface temperature (Mann et al., 2009) previously published by one of us (study co-author and RealClimate co-founder Mike Mann) that extend back to 900 AD (see “What we can learn from studying the last millennium (or so)”) to estimate the circulation (AMOC) intensity over the entire last 1,100 years (Fig. 3). This shows that despite the substantial uncertainties in the proxy reconstruction, the weakness of the flow after 1975 is unique in more than a thousand years, with at least 99% probability. This strongly suggests that the weak overturning is not due to natural variability but rather a result of global warming.
Figure 3. Time series of the temperature difference between the subpolar North Atlantic and the entire Northern Hemisphere, which can be interpreted as an indicator of the strength of the Atlantic circulation.
Also in 2014 we again find a remarkable cold bubble over the northern Atlantic – as a look at the NASA website shows. 2014 was globally the warmest year on record, 1 °C warmer than the average for 1880-1920. But the subpolar Atlantic was 1-2 °C colder than that baseline.
And even more recently, NOAA last week released the stunning temperature analysis for the past winter shown in Figure 4. That winter was globally the warmest since records began in 1880. But in the subpolar North Atlantic, it was the coldest on record! That suggests the decline of the circulation has progressed even further now than we documented in the paper.
Figure 4. Temperature anomaly map for the past December-January-February, from NOAA.
The role of Greenland
Another new aspect is the importance of the increasing mass loss of the Greenland ice sheet, which causes extra freshwater to enter the North Atlantic that dilutes the sea water. We have joined forces with Greenland expert Jason Box who has reconstructed the mass balance of the Greenland ice sheet since 1840 (Figure 6 of our paper, see also his blog). The ice loss amounts to a freshwater volume which should have made an important contribution to the observed decrease in salinity in the northern Atlantic – probably including the “great salinity anomaly” of the 1970s, famous amongst oceanographers.
Meltwater on the Greenland ice sheet. Photo: Ian Joughin.
What are the impacts of a slowdown?
The consequences of a large reduction in ocean overturning would look nothing like the Hollywood film The Day After Tomorrow. But they would not be harmless either – e.g., for sea level (Levermann et al., 2005) particularly along the US east coast (Yin et al., 2009), marine ecosystems, fisheries and possibly even storminess in Europe (Woollings et al., 2012). We have studied these consequences some years ago in an interdisciplinary project with colleagues from Bremerhaven, Hamburg and Norway – the results are summarized in Kuhlbrodt et al. (2009).
If our analysis is correct, then this indicates that climate models underestimate the weakening of the Atlantic circulation in response to global warming – probably because the flow in these models is too stable (see Hofmann and Rahmstorf, 2009). Although these models predict a significant weakening for the future, they do not suggest this as early as the observations show it (see Figure 2 of our paper). That the real flow may be more unstable than previously thought would be bad news for the future.
If the circulation weakens too much it can even completely break down – the AMOC has a well-known “tipping point” (Lenton et al., 2008). The latest IPCC report (just like the previous one) estimates a probability of up to 10% that this could happen as early as this century. However, this assessment is based on models that may underestimate the risk, as mentioned above. Expert surveys indicate that many researchers assess the risk higher than the (generally conservative) IPCC, as is the case for sea level. In a detailed survey (Kriegler et al., 2009), the 16 experts interviewed saw already at moderate global warming (2-4 °C) a probability of a ‘tipping’ (major reorganisation) of the flow between 5 and 40 percent. With strong global warming (4-8 °C) this probability was even estimated as between 20 and 65 percent.
Figure 5. Sea surface temperature anomaly on 20 March 2015. Note that this is relative to a baseline 1979-2000, which is already a cold period in the subpolar Atlantic. Source: Climate Reanalyzer.
Thermohaline Ocean Circulation (Encyclopedia of Quaternary Sciences)
And The Independent
Vox includes comments by some colleagues: Tom Delworth and Gerald Meehl
Peter Sinclair has posted a short video on our paper with interview clips with Mike Mann, Jason Box and myself
Climate Central weighs in with more comments from other scientists on our paper
And here a brand new paper on the impacts of an AMOC shutdown (hat tip to our reader Yvan Dutil)
By coincidence, this came out the same day as our paper: Ten years of ocean monitoring uncovers secrets of changing UK winters
Rahmstorf, S., Box, J., Feulner, G., Mann, M., Robinson, A., Rutherford, S., Schaffernicht, E. (2015). Exceptional twentieth-century slowdown in Atlantic Ocean Overturning Circulation, Nature Climate Change (online)
W.S. Broecker (1987). Unpleasant surprises in the greenhouse? Nature, vol. 328, pp. 123-126. http://dx.doi.org/10.1038/328123a0
C. Schleussner, A. Levermann, and M. Meinshausen (2015). Probabilistic projections of the Atlantic overturning, Climatic Change, vol. 127, pp. 579-586. http://dx.doi.org/10.1007/s10584-014-1265-2
M. Dima, and G. Lohmann (2010). Evidence for two distinct modes of large-scale ocean circulation changes over the last century, Journal of Climate, vol. 23, pp. 5-16. http://dx.doi.org/10.1175/2009jcli2867.1
S. Drijfhout, G.J. van Oldenborgh, and A. Cimatoribus (2012). Is a decline of AMOC causing the warming hole above the North Atlantic in observed and modeled warming patterns? Journal of Climate, vol. 25, pp. 8373-8379. http://dx.doi.org/10.1175/jcli-d-12-00490.1
M.E. Mann, Z. Zhang, S. Rutherford, R.S. Bradley, M.K. Hughes, D. Shindell, C. Ammann, G. Faluvegi, F. Ni (2009). Global signatures and dynamical origins of the Little Ice Age and Medieval Climate Anomaly, Science, 326, 1256-1260. http://dx.doi.org/10.1126/science.1177303
A. Levermann, A. Griesel, M. Hofmann, M. Montoya, and S. Rahmstorf (2005). Dynamic sea level changes following changes in the thermohaline circulation, Climate Dynamics, vol. 24, pp. 347-354, 2005. http://dx.doi.org/10.1007/s00382-004-0505-y
J. Yin, M.E. Schlesinger, and R.J. Stouffer (2009). Model projections of rapid sea-level rise on the northeast coast of the United States, Nature Geoscience, vol. 2, pp. 262-266. http://dx.doi.org/10.1038/ngeo462
T. Woollings, J.M. Gregory, J.G. Pinto, M. Reyers, and D.J. Brayshaw (2012). Response of the North Atlantic storm track to climate change shaped by ocean–atmosphere coupling, Nature Geoscience, vol. 5, pp. 313-317. http://dx.doi.org/10.1038/NGEO1438
T. Kuhlbrodt, S. Rahmstorf, K. Zickfeld, F.B. Vikebø, S. Sundby, M. Hofmann, P.M. Link, A. Bondeau, W. Cramer, and C. Jaeger (2009). An integrated assessment of changes in the thermohaline circulation, Climatic Change, vol. 96, pp. 489-537. http://dx.doi.org/10.1007/s10584-009-9561-y
M. Hofmann, and S. Rahmstorf (2009). On the stability of the Atlantic meridional overturning circulation, Proceedings of the National Academy of Sciences, vol. 106, pp. 20584-20589. http://dx.doi.org/10.1073/pnas.0909146106
T.M. Lenton, H. Held, E. Kriegler, J.W. Hall, W. Lucht, S. Rahmstorf, and H.J. Schellnhuber (2008). Tipping elements in the Earth’s climate system, Proceedings of the National Academy of Sciences, vol. 105, pp. 1786-1793. http://dx.doi.org/10.1073/pnas.0705414105
E. Kriegler, J.W. Hall, H. Held, R. Dawson, and H.J. Schellnhuber (2009). Imprecise probability assessment of tipping points in the climate system, Proceedings of the National Academy of Sciences, vol. 106, pp. 5041-5046. http://dx.doi.org/10.1073/pnas.0809117106
by Climate Change SOS, Daily Kos, April 30, 2015
In early March, the strongest wave of tropical convection ever measured (known as the Madden Julian Oscillation) by modern meteorology moved into the western Pacific from Indonesian waters bringing an outbreak of 3 tropical cyclones, including deadly category 5 Pam which ravaged the south Pacific islands of Vanuatu. This extreme outburst of tropical storms and organized thunderstorms pulled strong westerly winds across the equator, unleashing a huge surge of warm water below the ocean surface. Normally, trade winds blow warm water across the Pacific from the Americas to Australia and Indonesia, pushing up sea level in the west Pacific. When the trade winds suddenly reversed to strong westerlies, it was as if a dam burst, but on the scale of the earth's largest ocean, the Pacific. The front edge of that massive equatorial wave, called a Kelvin wave, is now coming ashore on the Americas.
Last year the largest Kelvin wave ever seen in the Pacific ocean developed in February. After it came ashore and the surge of warm water moved up the Pacific coast, the upwelling of nutrient rich cold water dramatically slowed, and marine life began starving up and down the coast of north America. As the warm water moved north from the equator it merged with an enormous mass of warm stagnant water dubbed "the blob" which had built up in the central north Pacific ocean under the mound of high barometric pressure known as the Pacific high. Because the Pacific high had expanded north of its normal position, possibly because of climate change, warm, stagnant low nutrient water covered a large percentage of the surface of the north Pacific ocean. That stagnant water came ashore on the coast of the Pacific northwest and Alaska as the surge of warm water from the Kelvin wave moved up the California coast. The warm stagnant water lacked nutrients to support the growth of krill and copepods which are at the bottom of the food chain. Species that fed on krill and copepods had little to eat. Juvenile birds were the first to be affected by the lack of food. The west coast marine die off is already a crisis but it's likely to get much worse this summer and fall as the surge of warm water moves up the coast from the huge Kelvin wave now coming ashore.
The forecast of a strong El Nino brings good news to California. NOAA's CFSv2 model is forecasting above well above normal precipitation for October through December, 2015. Because models are forecasting El Nino conditions to continue through January 2016 there is a good chance that heavy winter rains will break the California drought. The downside will be massive landslides and flooding in areas that have been affected by recent wild fires.
attribution: NASA MODIS
Three tropical cyclones churned the waters around Australia on March 11, 2015, including Pam, which reached category 5 and devastated the south Pacific islands of Vanuatu.
Detailed research in California has found that nutrient upwelling was at a minimum in the El Nino year of 1992 and the super El Nino year of 1998. A huge surge of warm water from an enormous deep equatorial wave called a Kelvin wave is now hitting the west coast of the Americas. A wave of similar size struck last year brought a massive marine die off to the west coast, but this year's die offs will likely be global because climate models are predicting a super El Nino. Credit NOAA.
"The Pacific Coast saw record numbers of dead Cassin’s Auklets this winter. " Audubon.
10,000 baby sea lions dead on one California island — Experts: “It’s getting crazy… This is a crisis… Never seen anything like it… Very difficult to see so much death” — TV: “Numbers skyrocketing at alarming rates”An unprecedented number of auklets, a tiny sea bird that dives for plankton, were found dead in Fall 2014, apparently of starvation, along the west coast from California to Canada. Nutrient poor warm waters are the probable cause of the lack of food.
Last year, beginning about Halloween, thousands of juvenile auklets started washing ashore dead from California's Farallon Islands to Haida Gwaii (also known as the Queen Charlotte Islands) off central British Columbia. Since then the deaths haven't stopped. Researchers are wondering if the die-off might spread to other birds or even fish.The warming that last year's huge Kelvin wave brought started a global coral bleaching event is likely to get much worse after this year's huge wave of warm water spreads up and down the coasts of north and south America.
"This is just massive, massive, unprecedented," said Julia Parrish, a University of Washington seabird ecologist who oversees the Coastal Observation and Seabird Survey Team (COASST), a program that has tracked West Coast seabird deaths for almost 20 years. "We may be talking about 50,000 to 100,000 deaths. So far."
“It started in 2014 – we had severe bleaching from July to October in the northern Marianas, bad bleaching in Guam, really severe bleaching in the north western Hawaiian Islands, and the first ever mass bleaching in the main Hawaiian Islands,” said said Mark Eakin, Noaa’s Coral Reef Watch coordinator.NOAA's CFSv2 model is forecasting a strong El Nino event will develop this summer and continue through 2015. Warm water along the west coast, combined with weaker than normal winds caused by El Nino will prevent nutrient rich cold water from welling up along the coast. Species that depend on nutrient upwelling will face starvation. Australia's Bureau of Meteorology has an excellent El Nino forecasting model which is also predicting a strong El Nino. Because the jet stream has already gone into an El Nino pattern by moving south over the eastern Pacific ocean and Mexico and further north than normal over the eastern Atlantic ocean, the likelihood of El Nino failing to strengthen is small. Last year's Kelvin wave failed to bring on a strong El Nino because trade winds in the south Pacific didn't weaken but this year they have and waters along the west coast of south America have already warmed. The south Pacific has moved out of the cool mode it was in a year ago.
“It then moved south, with severe bleaching in the Marshall Islands and it has moved south into many of the areas in the western south Pacific. Bleaching just now is starting in American Samoa. In Fiji we’re starting to see some, the Solomon Islands have seen some. We’ve already seen a big event."Bleaching takes place when corals are stressed due to changes in light, nutrients or temperature – though only the latter can cause events of this magnitude. This causes them to release algae, lose their colour and in some cases die off. It is a relatively rare occurrence. Large-scale bleaching was recorded in 1983, followed by the first global scale event in 1998. A second global wave came in 2010.
NOAA forecast of the departure from normal of Pacific ocean sea surface temperatures. NOAA's CFSv2 model predicts a strong El Nino with much above normal sea surface temperatures along the west coasts of south and north America up to January, 2016.
California is likely to get relief from the drought in November and December 2015.