RealClimate: Hottest years rankings: (1) 2010, (2) 2005, (3) 2007/1998, (4) 2013/2009/2003/2002, (5) 2013/2006/2003/1998

by Stefan Rahmstorf, RealClimate, January 27, 2014

The global temperature data for 2013 are now published. 2010 and 2005 remain the warmest years since records began in the 19th century. 1998 ranks third in two records, and in the analysis of Cowtan and Way, which interpolates the data-poor region in the Arctic with a better method, 2013 is warmer than 1998 (even though 1998 was a record El Nino year, and 2013 was neutral).

The end of January, when the temperature measurements of the previous year are in, is always the time to take a look at the global temperature trend. (And, as the Guardian noted aptly, also the time where the “climate science denialists feverishly yell [...] that global warming stopped in 1998.”) Here is the ranking of the warmest years in the four available data sets of the global near-surface temperatures (1):

Rank	NASA GISS	NOAA NCDC	HadCRUT4	Cowtan & Way
1	2010	2010	2010	2010
2	2005	2005	2005	2005
3	2007	1998	1998	2007
4	2002	2013	2003	2009
5	1998	2003	2006	2013

New this year: for the first time there is a careful analysis of geographical data gaps – especially in the Arctic there’s a gaping hole – and their interpolation for the HadCRUT4 data. Thus there are now two surface temperature data sets with global coverage (the GISTEMP data from NASA have always filled gaps by interpolation). In these two data series 2007 is ranked 3rd. Their direct comparison is shown in the figure below.

Figure 1 Global temperature (annual values) in the data from NASA GISS (orange) and from Cowtan & Way (blue), i.e., HadCRUT4 with interpolated data gaps.

One can clearly see the extreme year 1998, which (thanks to the record-El Niño) stands out above the long-term trend like no other year. But even taking this outlier year as starting point, the linear trend 1998-2013 in all four data sets is positive. Also clearly visible is 2010 as the warmest year since records began, and the minima in the years 2008 and 2011/2012. But just like the peaks are getting higher, these minima are less and less deep.

In these data curves I cannot see a particularly striking or significant current “warming pause”, even though the warming trend from 1998 is of course less than the long-term trend. Even in Nature, there was recently a (journalistic) contribution that in its introduction strongly overstated this alleged “hiatus”. It makes a good story that perhaps some cannot resist. (“Warming trend is somewhat reduced, but within the usual range of variation” simply does not make good headline.)

The role of El Niño and La Niña

The recent slower warming is mainly explained by the fact that in recent years the La Niña state in the tropical Pacific prevailed, in which the eastern Pacific is cold and the ocean stores more heat (2). This is due to an increase in the trade winds that push water westward across the tropical Pacific, while in the east cold water from the depths comes to the surface (see last graph here). In addition, radiative forcing has recently increased more slowly (more on this in the analysis of Hansen et al. – definitely worth a read).

NASA shows the following graphic, where you can see that the warmer years tend to be those with an El Niño in the tropical Pacific (red years), while the particularly cool years are those with La Niña (blue years).

Figure 2. The GISS data, with El Niño and La Niña conditions highlighted. Neutral years like 2013 are gray. Source: NASA.

Quality of the interpolation

How good is the interpolation into regions not regularly covered by weather stations? In any case, of course, better than simply ignoring the gaps, as the HadCRUT and NOAA data have done so far.  The truly global average is important, since only it is directly related to the energy balance of our planet and thus the radiative forcing by greenhouse gases. An average over just part of the globe is not.  The Arctic has been warming disproportionately in the last ten to fifteen years.

But how well the interpolation works we know only since the important work of Cowtan and Way. These colleagues have gone to the trouble of carefully validating their method. Although there are no permanent weather stations in the Arctic, there is intermittent data from buoys and and from weather model reanalyses with which they could test their method. For the last few decades and Cowtan and Way also make use of satellite data (more on this in our article on underestimated warming). I therefore assume that the data from Cowtan and Way is the methodologically best estimate of the global mean temperature which we currently have. This correction is naturally small (less than a tenth of a degree) and hardly changes the long-term trend of global warming – but if you look deeper into  shorter periods of time, it can make a noticeable difference. The comparison with the uncorrected HadCRUT4 data is shown in the figure below.

Figure 3. Comparison of interpolated and non-interpolated HadCRUT4 data, as moving averages over 12 months. Source: Kevin Cowtan, University of York.

And here’s a look at the last years in detail:

Figure 4. The interpolated HadCRUT4 data (annual average) from 1970. Source: Kevin Cowtan, University of York.

Following this analysis, 2013 was thus even warmer than the record El-Niño-year 1998.

Conclusion

• In all four data series of the global near-surface air temperature, the linear trend even from the extreme El Niño year 1998 is positive, i.e. shows continued warming, despite the choice of a warm outlier as the initial year.
• In all four data series of the global near-surface air temperature, 2010 was the warmest year on record, followed by 2005.
• The year 1998 is, at best, rank 3 – in the currently best data set of Cowtan & Way, 1998 is actually only ranked 7th. Even 2013 is – without El Niño – warmer there than 1998.

The German news site Spiegel Online presents these facts under the headline Warming of the air paused for 16 years (my translation). The headline of the NASA news release, NASA Finds 2013 Sustained Long-Term Climate Warming trend, is thus completely turned on its head.

This will not surprise anyone who has followed climate reporting of Der Spiegel in recent years. To the contrary – colleagues express their surprise publicly when a sensible article on the subject appears there. For years, Der Spiegel has acted as a gateway for dubious “climate skeptics” claims into the German media whilst trying to discredit top climate scientists (we’ve covered at least one example here).

Do Der Spiegel readers know more (as their advertising goes) – more than NASA, NOAA, Hadley Centre and the World Meteorological Organization WMO together? Or are they simply being taken for a ride for political reasons?

Footnotes

(1) In addition to the data of the near-surface temperatures, which are composed of measurements from weather stations and sea surface temperatures, there is also the microwave data from satellites, which can be used to estimate air temperatures in the troposphere in a few kilometers altitude. In the long-term climate trend since the beginning of satellite measurements in 1979, the tropospheric temperatures show a similar warming as the surface temperatures, but the short-term fluctuations in the troposphere are significantly different from those near the surface. For example, the El Niño peak in 1998 is about twice as high as in the surface data in the troposphere, see Foster and Rahmstorf 2011. In their trend from 1998 , the two satellite series contradict each other: UAH shows +0.05 °C per decade (a bit more than HadCRUT4), RSS shows -0.05 °C per decade.

(2) Another graphic (Figure 5) illustrates the change between El Niño and La Niña: the Oceanic Niño Index ONI, the standard index of NOAA to describe the seesaw in the tropical Pacific.

Figure 5. The ONI index. The arrows added by me point to some of the globally warm or cool years (compare Figure 1 or 4). Source: NOAA.

Weblinks

The global temperature jigsaw (an overview over the “pause” debate)
What ocean heating reveals about global warming

http://www.realclimate.org/index.php/archives/2014/01/global-temperature-2013/

WMO: 2001-2010 warmest decade since records began in 1850

2001-2010 warmest decade on record: WMO

AFP, March 23, 2012

GENEVA — Climate change has accelerated in the past decade, the UN weather agency said Friday, releasing data showing that 2001 to 2010 was the warmest decade on record.

The 10-year period was also marked by extreme levels of rain or snowfall, leading to significant flooding on all continents, while droughts affected parts of East Africa and North America.

"The decade 2001-2010 was the warmest since records began in 1850, with global land and sea surface temperatures estimated at 0.46 degrees Celsius above the long term average of 14.0 degrees Celsius (57.2 degrees Fahrenheit)," said the World Meteorological Organisation.

Nine of the 10 years also counted among the 10 warmest on record, it added, noting that "climate change accelerated" during the first decade of the 21st century.

The trend continued in 2011, which was the warmest year on record despite La Nina -- a weather pattern which has a cooling effect.

The average temperature in 2011 was 0.40 degrees Celsius above the long term average, said the WMO.

"This 2011 annual assessment confirms the findings of the previous WMO annual statements that climate change is happening now and is not some distant future threat," said WMO Secretary-General Michel Jarraud.

"The world is warming because of human activities and this is resulting in far-reaching and potentially irreversible impacts on our Earth, atmosphere and oceans," he added.

The UN weather agency noted that during the decade, "numerous weather and climate extremes affected almost every part of the globe with flooding, droughts, cyclones, heat waves and cold waves."

Historical floods hit Eastern Europe in 2001 and 2005, Africa in 2008, Asia and Australia in 2010. Global precipitation -- including rain or snow -- reached the second highest average since 1901. The highest average was recorded for the decade 1951-1960.

Meanwhile for the North Atlantic basin, the 10 years marked the highest level of tropical cyclone activity, including Hurricane Katrina which struck the United States in 2005 and Cyclone Nargis which hit Myanmar in 2008.

http://www.google.com/hostednews/afp/article/ALeqM5hqv_q4RxB9yyysWL-JvMrUjSfHYg

NASA Video Illustrates 130 Years of Global Warming, Hansen Expects New Global Temperature Record Within 3 Years

by Stephen Lacey, Climate Progress, January 27, 2012

In 1880, when modern global temperature records began, atmospheric carbon dioxide levels were at 285 parts per million. In 2011, they are were over 390 parts per million. That has trapped a lot of extra energy on earth — see “The Radiative Forcing of the CO2 Humans Have Put in the Air Equals 1 Million Hiroshima Bombs a Day.”

As we’ve spewed greenhouse gas emissions into the atmosphere at at a faster pace, global temperatures have accelerated upward, particularly since the 1970s. To illustrate this rise, NASA’s Goddard Institute for Space Studies released this fascinating video of 131 years of temperature records edited into a 30-second video.

“We know the planet is absorbing more energy than it is emitting,” said GISS Director James E. Hansen. “So we are continuing to see a trend toward higher temperatures. Even with the cooling effects of a strong La Niña influence and low solar activity for the past several years, 2011 was one of the 10 warmest years on record.”

Hansen said he expects record-breaking global average temperature in the next two to three years….  “It’s always dangerous to make predictions about El Niño, but it’s safe to say we’ll see one in the next three years,” Hansen said. “It won’t take a very strong El Niño to push temperatures above 2010.”

http://thinkprogress.org/romm/2012/01/27/413227/nasa-video-global-warming/ 

John Cook, Skeptical Science: Does record snowfall disprove global warming?

Does record snowfall disprove global warming?

by John Cook, Skeptical Science, March 7, 2010

The 2009/2010 winter saw a number of dramatic, record breaking snowstorms. Early February 2010 saw two "once in a 100 years" snowstorms hit Philadelphia, now being dubbed "Snowmageddon." Does record snowfall prove that global warming isn't happening? What do observations say? 2009 was the second hottest year on record. January 2010 was the hottest January in the UAH satellite record. Satellites data indicates last month was the second hottest February in the satellite record. Observations tell us that rumours of global warming's death have been greatly exaggerated.


Figure 1. UAH satellite measurement of near surface temperature. January 2010 is the hottest January in the satellite record. February 2010 is the second hottest February in the satellite record. Click on the image for larger version.

If global warming is still happening, why are some areas experiencing record snowfall events? As climate warms, evaporation from the ocean increases. This results in more water vapour in the air. Globally, atmospheric water vapour has increased by about 5% over the 20th century. Most of the increase has occurred since 1970 (IPCC AR4 3.4.2.1). This is confirmed by satellites that find the total atmospheric moisture content has been increasing since measurements began in 1988 (Santer 2007).


Figure 2. Change in water vapor percentage relative to the 1988 to 2004 period over the global ocean plus linear trend, measured by satellite (IPCC AR4 3.4.2.1).
 
The extra moisture in the air is expected to produce more precipitation, including more extreme precipitation events. Observations bear this out. A study of precipitation trends over the United States found that heavy precipitation events (over 50 mm in a day) have increased 20% over the 20th century (Groisman 2004). Most of this increase occured after 1970. Various  analyses of precipitation over the globe have similarly found a widespread increase in heavy precipitation days since 1950 (Alexander 2006, Groisman 2006).


Figure 3. Global number of days per year when precipitation was greater than 10 mm per day, expressed as an anomaly from the 1961-1990 reference period (Alexander 2006).

Snowstorms can occur if temperatures are in the range of -10 °C to 0 °C. Global warming decreases the likeliness of snowstorm conditions in warmer, southern regions. However, in northern, colder regions, temperatures are often too cold for very heavy snow so warming can bring more favourable snowstorm conditions (Kunkel 2008). This is borne out in observations. Over the last century, there has been a downward trend in snowstorms across the lower Midwest, South and West Coast. Conversely, there's been an increase in snowstorms in the upper Midwest East, and Northeast with the overall national trend also upwards (Changnon 2006).

To claim that record snowfall is inconsistent with a warming world betrays a lack of understanding of the link between global warming and extreme precipitation. Global temperatures in the last few months of record snowfall are some of the hottest on record. Warming causes more moisture in the air which leads to more extreme precipitation events. This includes more heavy snowstorms in regions where snowfall conditions are favourable. Far from contradicting global warming, record snowfall is predicted by climate models and consistent with our expectation of more extreme precipitation events.

Link:  http://www.skepticalscience.com/Does-record-snowfall-disprove-global-warming.html

Mountain Pine Beetle, British Columbia: A Climate Change Catastrophe

Mountain Pine Beetle: A Climate Change Catastrophe

Unfortunately, this video speaks very well for itself.  I have to wonder what is going on in Nebraska, North Dakota, Idaho, Washington.  I saw very unhealthy stands in the Wisconsin Dells last August.  I was pretty shocked.

Here in Vitória da Conquista, Bahia, Brazil, up on the plateau, all of the trees in this city of a certain species have died from some kind of beetle.  This happened in only the last 6 months, it went that fast.  There are four of these trees on my street.  It is weird to look out my window and see those bare branches. Our winter occurs in June through August, and it was so warm that in the middle of winter the sparrows were doing mating dances and the pomegranate tree in my garden put out fruit.  Our previous summer (November 2008 -- March 2009) was pretty cold, here, and I told everyone that they should appreciate it while it lasted.  That was the tail end of the La Nina. 


Link to YouTube video:  http://www.youtube.com/watch?v=MRSR5L5e28g

Menne et al., JGR 2010: On the reliability of the U.S. Surface Temperature Record

On the reliability of the U.S. Surface Temperature Record

by John Cook, Skeptical Science, January 22, 2010

The website surfacestations.org enlisted an army of volunteers, travelling across the U.S. photographing weather stations. The point of this effort was to document cases of microsite influence -- weather stations located near car parks, air conditioners and airport tarmacs and anything else that might impose a warming bias. While photos can be compelling, the only way to quantify any microsite influence is through analysis of the data. This has been done in On the reliability of the U.S. Surface Temperature Record (Memme 2010), published in the Journal of Geophysical Research. The trends from poorly sited weather stations are compared to well-sited stations. The results indicate that yes, there is a bias associated with poor exposure sites. However, the bias is not what you expect.

Weather stations are split into two categories: good (rating 1 or 2) and bad (ratings 3, 4 or 5). Each day, the minimum and maximum temperature are recorded. All temperature data goes through a process of homogenisation, removing non-climatic influences such as relocation of the weather station or change in the Time of Observation. In this analysis, both the raw, unadjusted data and homogenised, adjusted data are compared. Figure 1 shows the comparison of unadjusted temperature from the good and bad sites. The top figure (c) is the maximum temperature, the bottom figure (d) is the minimum temperature. The black line represents well sited weather stations with the red line representing poorly sited stations.

Figure 1. Annual average maximum and minimum unadjusted temperature change calculated using (c) maximum and (d) minimum temperatures from good and poor exposure sites (Menne 2010).

Poor sites show a cooler maximum temperature compared to good sites. For minimum temperature, the poor sites are slightly warmer. The net effect is a cool bias in poorly sited stations. Considering all the air-conditioners, BBQs, car parks and tarmacs, this result is somewhat a surprise. Why are poor sites showing a cooler trend than good sites?

The cool bias occurs primarily during the mid and late 1980s. Over this period, about 60% of USHCN sites converted from Cotton Region Shelters (CRS otherwise known as Stevenson Screens) to electronic Maximum/Minimum Temperature Systems (MMTS). MMTS sensors are attached by cable to an indoor readout device. Consequently, limited by cable length, they're often located closer to heated buildings, paved surfaces and other artificial sources of heat.

Investigations into the impact of the MMTS on temperature data have found that on average, MMTS sensors record lower daily maximums than their CRS counterparts, and, conversely, slightly higher daily minimums (Menne 2009). Only about 30% of the good sites currently have the newer MMTS-type sensors compared to about 75% of the poor exposure locations. Thus, it is the MMTS sensors that are responsible for the cool bias imposed on poor sites.

When the change from CRS to MMTS are taken into account, as well as other biases such as station relocation and Time of Observation, the trend from good sites show close agreement with poor sites.

Figure 2: Comparison of U.S. average annual (a) maximum and (b) minimum temperatures calculated using USHCN version 2 adjusted temperatures. Good and poor site ratings are based on surfacestations.org.

Does this latest analysis mean all the work at surfacestations.org has been a waste of time? On the contrary, the laborious task of rating each individual weather station enabled Memme 2010 to identify a cool bias in poor sites and isolate the cause. The role of surfacestations.org is recognised in the paper's acknowledgements in which they "wish to thank Anthony Watts and the many volunteers at surfacestations.org for their considerable efforts in documenting the current site characteristics of USHCN stations."

A net cooling bias was perhaps not the result the surfacestations.org volunteers were hoping for but improving the quality of the surface temperature record is surely a result we should all appreciate.

Link:  http://www.skepticalscience.com/On-the-reliability-of-the-US-Surface-Temperature-Record.html

NYT: Past Decade Warmest Ever, NASA Data Shows

Past Decade Warmest Ever, NASA Data Shows

by John Broder, New York Times, January 22, 2010

WASHINGTON — The decade ending in 2009 was the warmest on record, new surface temperature figures released Thursday by theNational Aeronautics and Space Administration show.
The agency also found that 2009 was the second warmest year since 1880, when modern temperature measurement began. The warmest year was 2005. The other hottest recorded years have all occurred since 1998, NASA said.

James E. Hansen, director of NASA’s Goddard Institute for Space Studies, said that global temperatures varied because of changes in ocean heating and cooling cycles. “When we average temperature over 5 or 10 years to minimize that variability,” said Dr. Hansen, one of the world’s leading climatologists, “we find global warming is continuing unabated.”

A separate preliminary analysis from another NASA office, the National Climatic Data Center, found that 2009 tied with 2006 as the fifth warmest year on record, based on measurements taken on land and at sea. The data center report, published earlier this week, also cited the years 2000 to 2009 as the warmest decade ever measured. The new temperature figures provide evidence in the scientific discussion of global warming but are not likely to be the last word on whether the planet’s temperature is on a consistent upward path.

Dr. Hansen, who has been an outspoken figure in the climate debate for years, has often been attacked by skeptics of global warming for what they charge is selective use of temperature data. The question of whether the planet is heating and how quickly was at the heart of the so-called “climategate” controversy that arose last fall when hundreds of e-mail messages from the climate study unit at the University of East Anglia in England were released without authorization.

Critics seized on the messages as evidence that, in their view, climate scientists were manipulating data and colluding to keep contrary opinion out of scientific journals. But climate scientists and political leaders affirmed what they called a broad-based consensus that the planet was growing warmer, and on a consistent basis, although with measurable year-to-year variations.

The NASA data released Thursday showed an upward temperature trend of about 0.36 °F (0.2 °C) per decade over the past 30 years. Average global temperatures have risen by about 1.5 °F (0.8 °C) since 1880.

“That’s the important number to keep in mind,” said Gavin Schmidt, a climatologist at Goddard. “The difference between the second and sixth warmest years is trivial because the known uncertainty in the temperature measurement is larger than some of the differences between the warmest years.”

Policy makers at the United Nations climate change summit conference in Copenhagen last month agreed on a goal of trying to keep the rise in average global temperatures to 3.6 °F, or 2 °C, to try to forestall the worst effects of global warming.


Link:  http://www.nytimes.com/2010/01/22/science/earth/22warming.html

James Hansen, Reto Ruedy, Makiko Sato, Ken Lo: If It’s That Warm, How Come It’s So Damned Cold?

If it’s that warm, how come it’s so damned cold?

James Hansen, Reto Ruedy, Makiko Sato, Ken Lo

The past year, 2009, tied as the second warmest year in the 130 years of global instrumental temperature records, in the surface temperature analysis of the NASA Goddard Institute for Space Studies (GISS). The Southern Hemisphere set a record as the warmest year for that half of the world.

Global mean temperature, as shown in Figure 1a, was 0.57 °C (1.0 °F) warmer than climatology (the 1951‐1980 base period). Southern Hemisphere mean temperature, as shown in Figure 1b, was 0.49 °C (0.88 °F) warmer than in the period of climatology.

See link for figures -- sorry I cannot copy them from the pdf file -- drat!!!

http://www.columbia.edu/~jeh1/mailings/2010/20100127_TemperatureFinal.pdf
Figure 1. (a) GISS analysis of global surface temperature change. Green vertical bar is estimated 95% confidence range (two standard deviations) for annual temperature change. (b) Hemispheric
temperature change in GISS analysis. (Base period is 1951–1980. This base period is fixed consistently
in GISS temperature analysis papers – see References. Base period 1961–1990 is used for comparison
with published HadCRUT analyses in Figures 3 and 4.)

The global record warm year, in the period of near‐global instrumental measurements (since the late 1800s), was 2005. Sometimes it is asserted that 1998 was the warmest year.

The origin of this confusion is discussed below.

There is a high degree of interannual (year‐to‐year) and decadal variability in both global and hemispheric temperatures. Underlying this variability, however, is a long‐term warming trend that has become strong and persistent over the past three decades.

The long‐term trends are more apparent when temperature is averaged over several years. The 60‐month (5‐year) and 132 month (11‐year) running mean temperatures are shown in Figure 2 for the globe and the hemispheres. The 5‐year mean is sufficient to reduce the effect of the El Nino–La Nina cycles of tropical climate. The 11‐year mean minimizes the effect of solar variability – the brightness of the sun varies by a measurable amount over the sunspot cycle, which is typically of 10–12 years' duration.

Complete paper at this link: http://www.columbia.edu/~jeh1/mailings/2010/20100127_TemperatureFinal.pdf

Joseph Romm: Hansen wants your feedback on “If It’s That Warm, How Come It’s So Damned Cold?”

Hansen wants your feedback on “If It’s That Warm, How Come It’s So Damned Cold?”

Essay by four NASA scientists explains why 2005 (not 1998) was the hottest year, what caused recent cold snap, and the source of the "gullibility" of those "so readily convinced of a false conclusion, that the world is really experiencing a cooling trend"

by Joseph Romm, Climate Progress, January 16, 2010

The bottom line is this: there is no global cooling trend. For the time being, until humanity brings its greenhouse gas emissions under control, we can expect each decade to be warmer than the preceding one. Weather fluctuations certainly exceed local temperature changes over the past half century. But the perceptive person should be able to see that climate is warming on decadal time scales.

The quote and figure are from a fascinating draft essay, “If It’s That Warm, How Come It’s So Damned Cold?” by NASA’s James Hansen, Reto Ruedy, Makiko Sato, and Ken Lo.  It is posted on Hansen’s Columbia University website, and he sent out a note to his email list asking for comments:

Criticisms are welcome. This is a draft essay that I wanted to get out because we are releasing our December and annual surface temperature analysis on the GISS web site. We will prepare a write-up on 2009 temperatures for the GISS web site next week.

If you post comments I’ll get them to him.

Yes, Dr. Ruedy had told me they were going to get their write-up out Friday (see “Breaking: 2009 hottest year on record in Southern Hemisphere and tied for second globally“).  But apparently there are just too many issues they wanted to address in it, including the long-term trend vs. the cold snap.  The trend is unmistakable, you might even say unequivocal:

The long‐term trends are more apparent when temperature is averaged over several years. The 60‐month (5‐year) and 132 month (11‐year) running mean temperatures are shown in Figure 2 for the globe [above] and the hemispheres. The 5‐year mean is sufficient to reduce the effect of the El Nino–La Nina cycles of tropical climate. The 11‐year mean minimizes the effect of solar variability – the brightness of the sun varies by a measurable amount over the sunspot cycle, which is typically of 10–12 years' duration.

The draft essay goes into great depth on how NASA knows 2005 was warmer than 1998 and why their dataset is better than the Hadley/CRU dataset (see also “Why are Hadley and CRU withholding vital climate data from the public?” and Finally, the truth about the Hadley/CRU data: “The global temperature rise calculated by the Met Office’s HadCRUT record is at the lower end of likely warming”).

There is a contradiction between the observed continued warming trend and popular perceptions about climate trends. Frequent statements include: “There has been global cooling over the past decade.” “Global warming stopped in 1998.” “1998 is the warmest year in the record.” Such statements have been repeated so often that most of the public seems to accept them as being true. However, based on our data, such statements are not correct.

The origin of this contradiction probably lies in part in differences between the GISS and HadCRUT temperature analyses (HadCRUT is the joint Hadley Research Centre, University of East Anglia Climate Research Unit temperature analysis). Indeed, HadCRUT finds 1998 to be the warmest year in their record. In addition, popular belief that the world is cooling is reinforced by cold weather anomalies in the United States in the summer of 2009 and cold anomalies in much of the Northern Hemisphere in December 2009.

Here we first show the main reason for the difference between the GISS and HadCRUT analyses. Then we examine the 2009 regional temperature anomalies in the context of global temperatures.

A key takeaway message is this:

Why are some people so readily convinced of a false conclusion, that the world is really experiencing a cooling trend? That gullibility probably has a lot to do with regional short‐term temperature fluctuations, which are an order of magnitude larger than global average annual anomalies.

Short-term weather fluctuations are vastly greater than the long-term global warming anomaly in the climate (so far).  Weather isn’t climate.

Link:  http://climateprogress.org/2010/01/16/hansen-global-warming-cooling-nasa-gisstemp/

Joseph Romm: The hottest decade ends and since there’s no Maunder mininum — sorry deniers! — the hottest decade begins

The hottest decade ends and since there’s no Maunder mininum — sorry deniers! — the hottest decade begins

2009 ends with a "sunspot surge" as solar cycle 24 revs up, though the sun is increasingly a bit player in the global warming trend

by Joseph Romm, Climate Progress, December 31, 2009

The figure is from Spaceweather.com, in its “Sunspot Surge” post.

The 2000s were  the hottest decade in recorded history by far — even though we’re at “the deepest solar minimum in nearly a century.”  The 2000s were a full 0.2 °C warmer than the 1990s, which of course had been the hottest decade on record, 0.14 °C warmer than 1980s (according to the dataset that best tracks planetary warming).  Hmm.  It’s almost like the warming is accelerating.

There’s little doubt the 2010s will be the hottest decade on record, barring multiple supervolcanoes.  Yet when the anti-science crowd isn’t perversely spending their time trying to stop all efforts to cut global warming pollution that might slow warming, they are perversely trying to convince the public and policymakers we’re not warming at all.  That’s why many of them have been rooting for this deep solar minimum to become a Maunder Minimum, to mute the warming signal and hence the motivation for action for a few more years.  Yes, they have a self-destructive streak.

In fact, even if total solar irradiance (TSI) never recovered, we wouldn’t have entered a period of cooling since, “the negative forcing, relative to the mean solar irradiance is equivalent to seven years of CO₂ increase at current growth rates,” as NASA noted in January 2009.  Heck, even with a La Niña and an unusually inactive sun, 2008 was almost 0.1 °C warmer than the hot decade of the 1990s as a whole.  And 2009 now seems likely to be the second hottest year on record after 2005.  Changes in the sun just ain’t the big dog anymore when it comes to driving climate change (see below).

When we last looked at the sun [please, don't try that at home], NASA was reporting that the sunspot cycle was about to come out of its depression, if a newly discovered mechanism for predicting solar cycles — a migrating jet stream deep inside the sun — proved accurate (see National Solar Observatory, NASA say no “Maunder Minimum”).

It now appears TSI is well on its way to recovering, as NASA and others had predicted.  Leif Svalgaard recently put up this figure (click to enlarge):

Spaceweather.com says of its sunspot figure at the top of the page:

The dark line is a linear least-squares fit to the data. If the trend continues exactly as shown (prediction: it won’t), sunspots will become a non-stop daily occurrence no later than February 2011. Blank suns would cease and solar minimum would be over.

If the past two years have taught us anything, however, it is that the sun can be tricky and unpredictable. Stay tuned for surprises.

Even as Solar Cycle 24 picks up, it won’t affect global temperatures quickly.  Again, as  NASA explained in January:

Because of the large thermal inertia of the ocean, the surface temperature response to the 10-12 year solar cycle lags the irradiance variation by 1-2 years. Thus, relative to the mean, i.e., the hypothetical case in which the sun had a constant average irradiance, actual solar irradiance will continue to provide a negative anomaly for the next 2-3 years.

Also, Solar Cycle 24 has recently been predicted to be on the wimpy side.

The sun simply isn’t a big player in driving recent warming.  As a major 2009 study found (see Another long-debunked denier talking point is debunked again: Changes in the Sun are not causing global warming):

According to this analysis, solar forcing contributed negligible long-term warming in the past 25 years and 10% of the warming in the past 100 years.

And a major 2007 study concluded:

Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.

Related scientific studies on the subject can be found on the excellent debunking website, Skeptical Science.  Here’s but a few:

• Erlykin 2009: “We deduce that the maximum recent increase in the mean surface temperature of the Earth which can be ascribed to solar activity is 14% of the observed global warming”
• Benestad 2009: “Our analysis shows that the most likely contribution from solar forcing a global warming is 7 ± 1% for the 20th century and is negligible for warming since 1980.”
• Lockwood 2008: “It is shown that the contribution of solar variability to the temperature trend since 1987 is small and downward; the best estimate is −1.3% and the 2σ confidence level sets the uncertainty range of −0.7 to −1.9%.”
• Lockwood 2008: “The conclusions of our previous paper, that solar forcing has declined over the past 20 years while surface air temperatures have continued to rise, are shown to apply for the full range of potential time constants for the climate response to the variations in the solar forcings.”
• Ammann 2007: “Although solar and volcanic effects appear to dominate most of the slow climate variations within the past thousand years, the impacts of greenhouse gases have dominated since the second half of the last century.”
• Lockwood 2007: “The observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability, whichever of the mechanism is invoked and no matter how much the solar variation is amplified.”
• Foukal 2006 concludes “The variations measured from spacecraft since 1978 are too small to have contributed appreciably to accelerated global warming over the past 30 years.”

By one recent estimate, human-caused greenhouse gas emissions are responsible for “80 to 120% of the warming” in recent decades (see “What percentage of global warming is due to human causes vs. natural causes?“)

Human-caused emissions are simply driving climate change to dangerous levels with forcings that dwarf previous natural forcings both in speed and scale (see “Humans boosting CO2 14,000 times faster than nature, overwhelming slow negative feedbacks“).

And that’s why the time to act is now, so every decade this century isn’t the hottest decade on record, with unimaginably catastrophic consequences for the health and well-being of our children and grandchildren and their children and grandchildren.

Link: http://climateprogress.org/2009/12/31/science-the-hottest-decade-ends-maunder-mininum-solar-cycle-24-global-warming/

Satellite Data Confirms November Warmth over the U.S.; Current Decade Likely Warmest in the Modern Record

Readers, I am borrowing this post from Brett Anderson at AccuWeather since I can only get this graph by asking someone outside of Brazil to send it to me -- the servers at this website will never let me in.  The second graphic is the scariest graphic on global warming that I have ever seen and continues to be although I have been looking at its updates for two years.


You can see the cyclical patterns of the the circulation of the warm and cooler ocean waters, and how over time, the waters are no longer cooling.  Not good.

Satellite Data Confirms November Warmth over the U.S.

by Brett Anderson, AccuWeather, Sunday, December 6, 2009

Remote Sensing Systems (RSS) has released their satellite measured, lower tropospheric temperature anomaly data for the month of November across the globe.

A global look at the lower tropospheric temperature anomalies across most of the globe, courtesy of RSS.


Overall, November ended up slightly warmer compared to normal globally, but the bigger story is how warm November was compared to normal from central to northeastern North America.

Other "warm" pockets can be seen over southeastern Australia, Scandinavia and out over the central Pacific, which is a reflection of the slowly strengthening El Nino.

Notable "cool" spots showed up over southern South America, Asia and Alaska.

Let's look at the actual numbers (temperature anomalies)............
Global (70 S to 82.5 N): +.328 °C
Continental U.S.: +1.242 °C, which makes this the warmest month compared to normal since March of 2007 and the warmest November since 2001. Based on the RSS temperature record going back to 1979.

Here is an updated look at the decadal trend of the lower tropospheric temperature anomaly by latitude. Note: A majority of the warming has been in the northern polar regions (increasing oranges/reds).

Also, note (circled) the distinct red (warming) in the lower latitudes during 1998 (strong El Nino) and the latest cooling in this same region during 2008 with the La Nina.

Current Decade Likely Warmest in the Modern Record

by Brett Anderson, AccuWeather, December 8, 2009

The current decade will probably end up as the warmest (combined land and sea surface) in the modern record globally, according to the World Meteorological Organization (WMO). Records go back to 1850.
The decade of the 2000s (2000-2009) was warmer than the 1990s, which in turn was warmer than the 1980s, according to the WMO press release that was issued today.

This preliminary information for 2009 is based on climate data from networks of land-based weather and climate stations, ships and buoys, as well as satellites.

Image courtesy of the World Meteorological Organization.


How about 2009?
This year will likely rank in the top 10 warmest since records were kept, and may end up as the 5th warmest.

--Only North America experienced cooler than normal conditions this year.

--Large parts of southern Asia and central Africa are likely to have their warmest year on record.
---------
The WMO global temperature analysis is based on three complementary datasets. One is the combined dataset maintained by both the Hadley Centre of the UK Met Office and the Climatic Research Unit, University of East Anglia, United Kingdom. Another dataset is maintained by the National Oceanic and Atmospheric Administration (NOAA) under the United States Department of Commerce, and the third one is from the Goddard Institute of Space Studies (GISS) operated by the National Aeronautics and Space Administration (NASA).

Link:  http://global-warming.accuweather.com/

World Meteorological Organization: 2000–2009, THE WARMEST DECADE

Press Release No. 869

For use of the information media
Not an official record

2000–2009, THE WARMEST DECADE

Geneva, 8 December 2009 (WMO) – The year 2009 is likely to rank in the top 10 warmest on record since the beginning of instrumental climate records in 1850, according to data sources compiled by the World Meteorological Organization (WMO). The global combined sea surface and land surface air temperature for 2009 (January–October) is currently estimated at 0.44°C ± 0.11°C (0.79°F ± 0.20°F) above the 1961–1990 annual average of 14.00°C/57.2°F. The current nominal ranking of 2009, which does not account for uncertainties in the annual averages, places it as the fifth-warmest year. The decade of the 2000s (2000–2009) was warmer than the decade spanning the 1990s (1990–1999), which in turn was warmer than the 1980s (1980–1989). More complete data for the remainder of the year 2009 will be analysed at the beginning of 2010 to update the current assessment.

This year above-normal temperatures were recorded in most parts of the continents. Only North America (United States and Canada) experienced conditions that were cooler than average. Given the current figures, large parts of southern Asia and central Africa are likely to have the warmest year on record.

Climate extremes, including devastating floods, severe droughts, snowstorms, heatwaves and cold waves, were recorded in many parts of the world. This year the extreme warm events were more frequent and intense in southern South America, Australia and southern Asia, in particular. La Niña conditions shifted into a warm-phase El Niño-Southern Oscillation (ENSO) in June. The Arctic sea ice extent during the melt season ranked the third lowest, after the lowest and second-lowest records set in 2007 and 2008, respectively.

This preliminary information for 2009 is based on climate data from networks of land-based weather and climate stations, ships and buoys, as well as satellites. The data are continuously collected and disseminated by the National Meteorological and Hydrological Services (NMHSs) of the 189 Members of WMO and several collaborating research institutions. The data continuously feed three main depository global climate data and analysis centres, which develop and maintain homogeneous global climate datasets based on peer-reviewed methodologies. The WMO global temperature analysis is thus based on three complementary datasets. One is the combined dataset maintained by both the Hadley Centre of the UK Met Office and the Climatic Research Unit, University of East Anglia, United Kingdom. Another dataset is maintained by the National Oceanic and Atmospheric Administration (NOAA) under the United States Department of Commerce, and the third one is from the Goddard Institute of Space Studies (GISS) operated by the National Aeronautics and Space Administration (NASA). The content of the WMO statement is verified and peer-reviewed by leading experts from other international, regional and national climate institutions and centres before its publication.

Final updates and figures for 2009 will be published in March 2010 in the annual WMO Statement on the Status of the Global Climate.

Regional temperature anomalies

The year 2009 (January–October) was again warmer than the 1961–1990 average all over Europe and the Middle East. China had the third-warmest year since 1951; for some regions 2009 was the warmest year. The year started with a mild January in northern Europe and large parts of Asia, while western and central Europe were colder than normal. Russia and the Great Lakes region in Canada experienced colder-than- average temperatures in February and January, respectively. Spring was very warm in Europe and Asia; April in particular was extremely warm in central Europe. Germany, the Czech Republic and Austria reported temperature anomalies of more than +5°C, breaking the previous records for the month in several locations.

The European summer was also warmer than the long-term average, particularly over the southern regions.

Spain had the third-warmest summer, with hotter summers reported only in 2003 and 2005. Italy recorded a strong heatwave in July, with maximum temperatures above 40°C, and some local temperatures reaching 45°C. A heatwave at the beginning of July affected the United Kingdom, France, Belgium and Germany, and some stations in Norway experienced new maximum temperature records.

India had an extreme heatwave event during May, which caused 150 deaths. A heatwave hit northern China during June, with daily maximum temperatures above 40°C; historical maximum temperature records were broken for the summer in some locations.

In late July many cities across Canada recorded their warmest daily temperatures. Vancouver and Victoria set new records, reaching 34.4°C and 35.0°C, respectively. Alaska also had the second-warmest July on record. Conversely, October was a very cold month across large parts of the United States. For the nation as a whole, it was the third-coolest October on record, with an average temperature anomaly of -2.2°C (-4.0°F). Similarly, a very cold October was reported in Scandinavia, with mean temperature anomalies ranging from -2°C to -4°C.

The austral autumn (March to May) was extremely warm in Argentina, Uruguay, Paraguay and southern Brazil. With daily temperatures ranging from 30°C to 40°C, several records were broken during this season. By the end of October, an extreme weather situation affected north and central Argentina, producing unusually high temperatures (above 40°C). Conversely, November was abnormally cold in the southern part of the region, with some rare and late snowfalls.

So far, Australia has had the third-warmest year on record. The year 2009 was marked by three exceptional heatwaves, which affected south-eastern Australia in January/February and November, and subtropical eastern Australia in August. The January/February heatwave was associated with disastrous bushfires that caused more than 173 fatalities. Victoria recorded its highest temperature with 48.8°C. The northern region experienced a cold summer, however, with anomalies reaching -3°C to -4°C in some places. Winter was exceptionally mild over much of Australia. Maximum temperatures were well above normal across the entire continent, reaching 6°C to 7°C above normal in some parts. The national maximum temperature anomaly of +3.2°C was the largest ever recorded for any month.

Severe droughts

China suffered its worst drought in five decades. Water levels in parts of the Gan River and Xiangjiang River were the lowest in the past 50 years. In India the poor monsoon season caused severe drought impacts in 40 per cent of the districts. The north-western and north-eastern parts of the country were badly affected. It was reported to be one of the weakest monsoon seasons since 1972.

In East Africa the drought led to massive food shortages. In Kenya the drought was responsible for severe damage to livestock and a 40% decline in the maize harvest.

In North America, Mexico experienced severe-to-exceptional drought conditions by the month of September. In the United States, the western region was the most affected by a moderate-to-exceptional drought by the end of October. Nevertheless, the total area affected by drought in the United States during October was the second-smallest value recorded in this decade.

Drought in Central Argentina caused severe damage to agriculture, livestock and water resources. The situation was most severe at the end of October, with very high temperatures reported as well.

Over the key agricultural areas of the Murray-Darling Basin and the south-western part of Western Australia, rainfall was generally below normal. The passage of another year without any sustained above-normal rainfall has seen long-term rainfall deficits continuing in south-eastern Australia. Sustained dry conditions in the Murray-Darling Basin have now continued for nine years.

Intense storm events and precipitation

At the end of January, Spain and France were severely affected by winter storm Klaus, the worst extra-tropical storm in a decade, with winds similar to a category 3 hurricane. Another winter storm combined with heavy snowfall caused severe damage in western Europe and resulted in serious disruptions of air and rail traffic in several countries. In late spring and summer a large number of thunderstorms with heavy rain, hail and tornadoes caused local flooding and significant damage across Germany. In September, several parts of the Mediterranean region were affected by extreme rainfall events. Total rainfall of more than 300mm was recorded in less than 48 hours in one location of south-eastern Spain, where the long-term average for total annual precipitation does not exceed 450 mm. During the same month, intense rainfall caused devastating damage to infrastructure in several parts of northern Africa, including Algeria, Morocco and Tunisia. In a similar pattern, the highest September rainfall recorded in 80 years produced severe flash floods in north-western Turkey. November brought severe flooding to northern areas of the United Kingdom, and a new 24-hour precipitation record was set for the country.

During the beginning of the year heavy rainfall was observed in Colombia, producing landslides and widespread floods. North-east Brazil was severely affected by heavy rainfall and flooding in April and May. Later, in July, a severe snowstorm hit the southern part of Argentina; it was the worst snowstorm in 15 years. During the austral spring, particularly in November, continuous heavy and intense rainfall was seen in north-eastern Argentina, southern Brazil and Uruguay, causing flooding in many places and affecting more than 15,000 people. Total monthly precipitation records were broken, with rainfall exceeding more than 500mm in many locations.

In Canada, Ontario experienced a record number of witnessed tornadoes and a record number of related fatalities. Canadian avalanches were almost double the yearly average for the past decade and the worst since 2002–2003. A total of 25 deaths made it one of the deadliest seasons. The northern plains region of the United States was affected by record flooding during the month of March. As a whole, the United States recorded the wettest October in 115 years.

In Central America, an intense storm in El Salvador in November, associated in part with Hurricane Ida, produced deadly floods and landslides that claimed 192 lives.

In Asia, after the weak 2009 monsoon season, southern India recorded severe flooding due to incessant rain in late September and the first week of October, and more than 250 lives were lost. On the other hand, northern China was severely affected by a snowstorm that occurred during the first half of November as part of a strong cold wave. These snowfalls were one month earlier than normal, breaking local weather records.

In western Africa, heavy and intense rainfall in September caused flooding that affected more than 100,000 people. The worst flooding was observed in Burkina Faso, where 263 mm of rain was recorded in less than 12 hours, breaking a record set 90 years ago. Further south on the continent, nearly 1 million people in Zambia and Namibia were affected by torrential rain that caused rivers to overflow their banks, flooding homes and cropland.

Australia was also affected by local flooding. Coastal Queensland and New South Wales were the hardest hit by several heavy rain events, with daily rainfall totals in excess of 300 mm. On the other hand, numerous duststorms affected eastern Australia in the second half of September and early October, as regular strong winds transported dust from northern South Australia over the eastern states. The most severe duststorm occurred on 22–23 September and covered large parts of New South Wales and Queensland, where the visibility was reduced to 100–200m in both Sydney and Brisbane.

End of La Niña and Development of El Niño

La Niña-like conditions were present in early 2009, followed by the development of El Niño patterns starting in June 2009. During June–September 2009, sea surface temperatures were generally about 1°C warmer than the long-term average across the central and eastern equatorial Pacific. An El Niño event is currently underway, with the early phase of the event holding steady at weak-to-moderate levels through July–September. During October, almost all indicators of El Niño became noticeably stronger.

Tropical cyclone season

The 2009 Atlantic hurricane season closed with the fewest named storms and hurricanes since 1997, most likely due to the unfavourable cyclonic conditions caused in part by El Niño. A total of nine named tropical storms were formed, including three hurricanes, two of which were major hurricanes at Category 3 strength or higher. (The averages are 11, 6 and 2, respectively).

In the East Pacific, 20 named tropical storms were recorded, eight of which evolved into hurricanes and five of which became major hurricanes (The averages are 16, 9 and 4, respectively.)

In the western North Pacific, 22 named tropical storms have been recorded so far, and 13 of them reached the intensity of typhoon, compared to the long-term averages of 27 and 14, respectively. Heavy precipitation associated with typhoons Ketsana and Parma was observed across the south of Luzon Island in the Philippines. The resulting flood disaster caused more than 900 fatalities in total. In August, Typhoon Morakot swept across Taiwan Province of China and caused more than 400 deaths and severe damage to agriculture and infrastructure. Hundreds of roads and bridges on the island were destroyed by floods.

The Australian and South Indian Ocean cyclone seasons recorded near-average activity. In the Australian region, there were 10 systems during this season, with Hamish the most significant one, although it did not make landfall. It reached category 5 intensity and was the most intense cyclone observed off the eastern Queensland coast since 1918.

Third-lowest Arctic sea ice

According to scientific measurements, Arctic sea ice has declined dramatically over the past 30 years at least, with the most extreme decline seen in the summer melt season. Arctic sea ice extent during the 2009 melt season was 5.10 million km2, which is the third-lowest on record after the 2007 record (4.3 million km2) and 2008 (4.67 million km2), since satellite measurements began in 1979.

Link:  http://www.wmo.int/pages/mediacentre/press_releases/pr_869_en.html