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Friday, January 31, 2014

No "hiatus" (pause/stop) in global ocean warming up to year 2013

Although much of the public focus regarding global warming is on the temperature increase near Earth's surface, the Arctic sea ice decrease, global glacier retreat or other phenomena at the surface, which are more visible to the human eye, from a point of view of physics, the heating up of the oceans is the most important factor regarding the changes in the energy balance of the Earth system. About 90% of the energy accumulation due to the perturbation in the radiative balance at the top of the atmosphere, caused by the increasing greenhouse gases in the atmosphere, is taking place in the oceans[1]. The importance of the oceans arises from their capability to store an enormous amount of heat due to the high specific heat capacity of water combined with the large mass of water in the oceans. To put things in perspective, the heat increase related to warming up only the upper most 3.5 meters of the global ocean body by x degrees is sufficient to warm up the whole mass of the atmosphere by about the same amount of x degrees.

Monitoring the oceans gives crucial information about the ongoing climate change in the Earth system. Following figure shows the global average of the annually averaged temperature anomaly in the oceans between the surface and three different depths, 0-100 meters, 0-700 meters, and 0-2000 meters over time, based on data provided by Ocean Climate Laboratory of the National Oceanic and Atmospheric Administration (NOAA). The figure includes the year 2013 as the most recent data point. The colored shadings show the standard error of the data times two. The black lines display local regression (Loess) fits with the 95% confidence intervals of the fits as grey shadings. The graphic was created using the package ggplot2[2] of the statistical computing and graphics environment R.
 
(Data source: NOAA/NESDIS/NODC Ocean Climate Laboratory,  http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/)

A few things can be see in the figure:

1. The temperature increase, which is visible in the oceans for the average over 100, 700, and 2000 meters depth since the mid 1970s is largest in the upper most 100 meters and becomes smaller with adding deeper layers to the averaging. The perturbation of the energy balance comes from the top and takes decades to penetrate into deeper layers of the oceans.

2. The temperature increase has been nearly linear for the average over the upper most 100 meters depth for the last decades, amounting to about 0.07 Kelvin per decade. To put things in perspective again, the same amount of heat related to this average temperature increase in those 100 meters would increase the average temperature of the whole atmospheric mass by about 2 Kelvin per decade. Luckily for humankind, most of this accumulated heat will not warm up the atmosphere, but penetrate into the deeper layers of the oceans. The exact amount of atmospheric warming in the next decades and centuries will depend on how efficiently heat accumulated in the upper layers of the oceans is being sequestered into the deeper layers of the oceans.

3. Because of this quasi linearity of the temperature increase in the upper most 100 meters, one can conclude that the increase has been accelerating between a depth of 100 and 700 meters. It is not possible to conclude whether an acceleration is present between 700 and 2000 meters depth, since the acceleration seen for the average over 2000 meters depth could come from the acceleration in the layer between 100 and 700 meters.

4. The globally averaged ocean temperature anomaly in the upper most 100 meters shows large interannual variability. The temperature swings can amount to about 0.2 Kelvin within a few years, for example between the years 1998 and 2004.

5. No "hiatus" of the ocean warming is visible in the new century for any of the temperature averages over the various depths. The confidence interval for the upper most 100 meters allows for some lowering of the temperature increase after the year 2005 with a low probability (but equally for some acceleration of the temperature anomaly).

In recent years, the talk has been a lot about the fraction of the energy sequestered into the deep and abyssal layers of the oceans (the so called "missing heat"). In my opinion, there has been some misdirection in the talk about the consequences of this regarding global warming at the surface. The argument has been put forward that concerns about global warming were exaggerated, since the deep oceans interacted with the atmosphere only on long time scales and the heat sequestered into the deep oceans was not coming back to the surface. However, it should be clear from the above that the heat accumulated in the deep oceans is not needed for continuing global warming at the surface and of the lower atmosphere. There is plenty of accumulated heat around in the upper layers of the oceans, which interact with the atmosphere on much shorter time scales, particularly the layers of the oceans which are above the thermocline in the oceans. The amount of heat accumulated in the upper layers of the oceans is more than sufficient for global warming at the surface and in the troposphere to continue for the decades ahead. This heat accumulation has not stopped and it will not stop as long as the amount of greenhouse gases in the atmosphere is increasing unabated due to human activities.

[1] Trenberth, K. E. and Fasullo, J. T. (2013), An apparent hiatus in global warming? Earth's Future. doi: 10.1002/2013EF000165.
[2] Wickham, H. (2009). ggplot2: Elegant graphics for data analysis. Springer New York,  http://had.co.nz/ggplot2/book.

Thursday, January 23, 2014

The story of my visit at Bob Tisdale's blog "Climate Observations"

Bob Tisdale is a little bit a strange fellow. He has a very odd belief that global warming, including the one of the oceans is caused by the El Nino-La Nina (or ENSO - El Nino Southern Oscillation) cycle. El Nino is characterized by a strong ocean heat and sea surface temperature anomaly in the Central and Eastern equatorial Pacific ocean. La Nina is the counterpart, characterized by a negative heat and sea surface temperature anomaly. The equatorial Pacific produces El Ninos and La Ninas every few years, with global reach through the atmospheric circulation, leading to temperature and precipitation anomalies even in remote regions of the planet, mediated through so called teleconnections. Sometimes warm or cold phases occurs in a row only interrupted by neutral conditions. It is a major mode of internal chaotic variability in the ocean-atmosphere system. Bob Tisdale understands as much. However, he does not seem to understand that El Nino-La Nina cannot generate by itself a global ocean warming trend, because the ocean does not heat itself. A net influx of energy into the oceans is needed to cause a secular warming trend of the whole body of ocean water. The energy must come from somewhere. Bob Tisdale cannot explain where it comes from. The axiom here is, like for all the AGW-"skeptics", global (ocean) warming cannot, never ever, be caused by the radiation effect of increasing anthropogenic greenhouse gases. All the arguments are built around this axiom.

This figure (added to the post after original posting) shows the increase in the ocean heat content since 1955, for which needs to be explained what the energy source for all the heating of the   oceans is:

I paid a visit at Bob Tisdale's blog, because I accidentally had seen that he had written and published on his blog an open letter to Daily Show host Jon Stewart who had made fun of AGW-denialism (here and here). After introducing himself, what an important personality he was, in the AGW-denial blogosphere, who even publishes at such an important blog as wattsupwiththat, Bob Tisdale explained to Jon Stewart how utterly wrong established climate science was regarding anthropogenic global warming.

Well, I had had the impression before that Bob Tisdale was someone among the AGW-"skeptics" with whom one at least could talk and who is able to maintain civility, damn was I wrong. What a bully and jerk, filled with delusions of grandeur, and at the same time with the need of getting reassured from his comrades. He very quickly started to show the usual reaction of fake skeptics, when they are losing the argument. He resorted to ad hominem attacks and other evasion tactics. Apparently, when he felt that the lack of physical soundness in his "theory" was pointed out too much and confronted with the inconvenient reality of empirical data, it turned out he is just another one who can't take it when he is being contradicted:
 

Tuesday, September 10, 2013

An independent confirmation of global land warming, not using temperatures from meteorological stations

It has been hypothesized in some scientific publications (e.g., Pielke et al, JGRA, 2007, doi:10.1029/2006JD008229) and sometimes outright asserted (by AGW "skeptics" or in some media outlets; e.g., here, here, and here) that temperature analyses like GISTEMP, HadCRUT, or NCDC were not reliable, and the global warming, seen in these analyses over the last century, using direct temperature measurements from meteorological stations was largely just an artefact of faulty measurements, data adjustments (homogenization), the urban heat island effect, and other factors.

Gilbert P. Compo, Prashant D. Sardeshmukh, Jeffrey S. Whitaker, Philip Brohan, Philip D. Jones, and Chesley McColl have just published a new study (for the abstract: Compo et al., GRL, 2013, doi:10.1002/grl.50425), where the land near surface air temperature is derived using a state-of-the-art data assimilation system (20th Century Reanalysis). The temperature is calculated from other variables (surface pressure) and parameters in the reanalysis. The measured land surface air temperature is not part of the input data. Thus, any possible contamination of the measured land near surface air temperature by other factors than the state of the atmosphere does not have any effect on the land near surface temperatures calculated in the reanalysis system. The correlation between the land near surface temperature, calculated from other variables in the data assimilation system, and the land near surface temperature data series, derived using direct measurements over land is very high. This increases the confidence in that the statistically significant global warming trend of the atmosphere near the surface, seen in the GISTEMP, HadCRUT, or NCDC analyses over the last century is real, and those data sets can be used as reliable references for other scientific analyses.

  



Wednesday, August 7, 2013

American Geophysical Union's statement on human-induced climate change

The American Geophysical Union (AGU) has revised and reaffirmed its position on climate change caused by human activities, which was adopted for the first time in the year 2003. Position statements like this by the AGU expire after four years, unless it is reaffirmed. I personally agree with this statement. Here, I document the text:

"Human-induced climate change requires urgent action.

Humanity is the major influence on the global climate change observed over the past 50 years. Rapid societal responses can significantly lessen negative outcomes.

'Human activities are changing Earth’s climate. At the global level, atmospheric concentrations of carbon dioxide and other heat-trapping greenhouse gases have increased sharply since the Industrial Revolution. Fossil fuel burning dominates this increase. Human-caused increases in greenhouse gases are responsible for most of the observed global average surface warming of roughly 0.8°C (1.5°F) over the past 140 years. Because natural processes cannot quickly remove some of these gases (notably carbon dioxide) from the atmosphere, our past, present, and future emissions will influence the climate system for millennia.

Extensive, independent observations confirm the reality of global warming. These observations show large-scale increases in air and sea temperatures, sea level, and atmospheric water vapor; they document decreases in the extent of mountain glaciers, snow cover, permafrost, and Arctic sea ice. These changes are broadly consistent with long-understood physics and predictions of how the climate system is expected to respond to human-caused increases in greenhouse gases. The changes are inconsistent with explanations of climate change that rely on known natural influences.

Climate models predict that global temperatures will continue to rise, with the amount of warming primarily determined by the level of emissions. Higher emissions of greenhouse gases will lead to larger warming, and greater risks to society and ecosystems. Some additional warming is unavoidable due to past emissions.

Climate change is not expected to be uniform over space or time. Deforestation, urbanization, and particulate pollution can have complex geographical, seasonal, and longer-term effects on temperature, precipitation, and cloud properties. In addition, human-induced climate change may alter atmospheric circulation, dislocating historical patterns of natural variability and storminess.

In the current climate, weather experienced at a given location or region varies from year to year; in a changing climate, both the nature of that variability and the basic patterns of weather experienced can change, sometimes in counterintuitive ways -- some areas may experience cooling, for instance. This raises no challenge to the reality of human-induced climate change.

Impacts harmful to society, including increased extremes of heat, precipitation, and coastal high water are currently being experienced, and are projected to increase. Other projected outcomes involve threats to public health, water availability, agricultural productivity (particularly in low-latitude developing countries), and coastal infrastructure, though some benefits may be seen at some times and places. Biodiversity loss is expected to accelerate due to both climate change and acidification of the oceans, which is a direct result of increasing carbon dioxide levels.

While important scientific uncertainties remain as to which particular impacts will be experienced where, no uncertainties are known that could make the impacts of climate change inconsequential. Furthermore, surprise outcomes, such as the unexpectedly rapid loss of Arctic summer sea ice, may entail even more dramatic changes than anticipated.

Actions that could diminish the threats posed by climate change to society and ecosystems include substantial emissions cuts to reduce the magnitude of climate change, as well as preparing for changes that are now unavoidable. The community of scientists has responsibilities to improve overall understanding of climate change and its impacts. Improvements will come from pursuing the research needed to understand climate change, working with stakeholders to identify relevant information, and conveying understanding clearly and accurately, both to decision makers and to the general public.'

Adopted by the American Geophysical Union December 2003; Revised and Reaffirmed December 2007, February 2012, August 2013."

Friday, July 12, 2013

Emerging new El Nino?

There has been some interesting development in the equatorial subsurface temperatures in the Pacific for the last two months. The positive temperature anomaly, which has been dominant in the upper 300 meters of the equatorial water body of the Western Pacific has spread eastward. Now we have a positive subsurface anomaly over the whole longitude range from 130E to 100 W. Only the far Eastern Pacific still shows a negative anomaly.






















(Source: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf, pg. 11)

The last model simulations are from June 2013. Most of the models predicted ENSO neutral conditions through 2013 back then.





















(Source: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf, pg. 26)

I am curious what the new model simulations, initialized with updated input data are going to say.

If one looks at the table of cold and warm episodes of ENSO, there has not been any period longer than four years from the end of an El Nino to the start of the following El Nino, going back to the year 1950. We are in the third year since the end of the last El Nino episode now. If it does not happen this year a new El Nino really will be due next year. Otherwise it would be unusual, if none occured compared to the frequency of occurrence for the period between 1950 and present.


Wednesday, July 10, 2013

AGW denier Marc Morano of Climate Depot and CFACT suggests, "global warming skeptics" are defined by fantasies about lynching climate scientists

Besides Morano did not get the facts right with respect to my employment, since I am not a NASA scientist (I am a Columbia University scientist at GISS), why am I saying this? Because Morano asserts on the Climate Depot website, "NASA scientist Jan Perlwitz publicly warns global warming skeptics, 'I shoot you dead'".


The actual fact is that I strongly responded on my own behalf to a lynch fantasy against climate scientists (which came combined with a delusional analogy to Nazi-Germany), articulated by a specific anonymous individual with the alias Allencic who said,



















Morano's claim my response to Allencic's lynch fantasy was addressed at "global warming skeptics" is a lie. Thus, when Morano interprets my response to this as a "warning" against "global warming skeptics" in general, he suggests this kind of lynch fantasies against climate scientists was a defining feature of "global warming skeptics". I did not say, and I do not think it was.

Also, by displaying my statement as something condemnable, even though it was a conditional statement for the case the addressed individual really tried to tar, feather and torch me, i.e., murder me, because I was a climate scientist, Morano also suggests that I did not have any right to self-defense in such a situation. Thus, AGW denier Marc Morano, who is paid by the conservative think thank  Committee for a Constructive Tomorrow (CFACT) for spreading his propaganda and lies on his website, implicitly suggests that climate scientists did not have a right to self-defense, when someone tried to murder them.

Marc Morano is an appalling example of lack of ethics and honesty on the side of the AGW deniers.


Statement of Macquarie University regarding the termination of Professor Murry Salby

Yesterday, anti-science blogger Anthony Watts of wattsupwiththat.com posted an article, "Professor Murry Salby, who is critical of AGW theory, is being disfranchised, exiled, from academia in Australia", in which Watts claims that Murry Salby was wronged by Macquarie University. The claim is based solely on assertions in an email by Salby to Anthony Watts. I participated in this thread until I got permanently banned, saying that I do not believe Salby's accusations just at face value. The anti-science crowd of "skeptics", being not very skeptical at this point, rushed to the usual judgement, ranting about the evil establishment suppressing "the truth" and punishing critical scientists. In one case the desire of violence against those evil climate scientists who say anthropogenic global warming was real, was articulated.

I think, one should not just listen to what Salby claims, one also should listen what the other side has to say. If Salby was wronged he can and should choose the legal means available to him. But I am not going to assume he was wronged just because he claims so in some email to an AGW denier website.

Macquarie University has released following statement regarding the matter on July 10, 2013, which reads,

"Macquarie University does not normally comment on the circumstances under which employees leave the University. However, we feel in this instance it is necessary to do so in order to correct misinformation.

The decision to terminate Professor Murry Salby’s employment with Macquarie University had nothing to do with his views on climate change nor any other views. The University supports academic freedom of speech and freedom to pursue research interests.

Professor Salby’s employment was terminated firstly, because he did not fulfil his academic obligations, including the obligation to teach. After repeated directions to teach, this matter culminated in his refusal to undertake his teaching duties and he failed to arrive at a class he had been scheduled to take.

The University took this matter very seriously as the education and welfare of students is a primary concern. The second reason for his termination involved breaches of University policies in relation to travel and use of University resources.

The termination of his employment followed an extensive and detailed internal process, including two separate investigations undertaken by a committee chaired by a former Australian Industrial Relations Commissioner and including a union nominee."