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rhinoceros
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Climate change scientific consensus: It's real
« on: 2005-06-27 09:26:11 » |
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USA Today says:
http://www.usatoday.com/news/opinion/editorials/2005-06-14-our-view_x.htm
The Bush administration's mantra on climate change is this: The science is not yet in to prove a link between man's gas-and-coal guzzling habits and rising global temperatures that are causing glaciers to shrink, polar ice caps to melt and seas to rise.
Yet, as USA TODAY's Dan Vergano reported Monday, not only is the science in, it is also overwhelming. Last week, the National Academy of Sciences and 10 other leading world bodies said there is "significant global warming" that requires urgent action.
<snip>
Talk about the modern-day equivalent of the flat-Earth brigade.
<snip>
[rhinoceros]
On June 7 2005, the U.S. National Academy of Sciences and 10 other significant scientific bodies from different countries made a declaration of consensus that "there is now strong evidence that significant global warming is occurring" and that "It is likely that most of the warming in recent decades can be attributed to human activities".
Note that these are neither green organizations, nor government services, nor institutions specifically funded to promote a particular claim.
Joint Science Academies’ Statement:
Global Response to Climate Change
7 June 2005
http://nationalacademies.org/onpi/06072005.pdf
Climate change is real
There will always be uncertainty in understanding a system as complex as the world’s climate. However there is now strong evidence that significant global warming is occurring1. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)2. This warming has already led to changes in the Earth's climate.
The existence of greenhouse gases in the atmosphere is vital to life on Earth – in their absence average temperatures would be about 30 centigrade degrees lower than they are today. But human activities are now causing atmospheric concentrations of greenhouse gases – including carbon dioxide, methane, tropospheric ozone, and nitrous oxide – to rise well above pre-industrial levels. Carbon dioxide levels have increased from 280 ppm in 1750 to over 375 ppm today – higher than any previous levels that can be reliably measured (i.e. in the last 420,000 years). Increasing greenhouse gases are causing temperatures to rise; the Earth’s surface warmed by approximately 0.6 centigrade degrees over the twentieth century. The Intergovernmental Panel on Climate Change (IPCC) projected that the average global surface temperatures will continue to increase to between 1.4 centigrade degrees and 5.8 centigrade degrees above 1990 levels, by 2100.
Reduce the causes of climate change
The scientific understanding of climate change is now sufficiently clear to justify nations taking prompt action. It is vital that all nations identify cost-effective steps that they can take now, to contribute to substantial and long-term reduction in net global greenhouse gas emissions.
Action taken now to reduce significantly the build-up of greenhouse gases in the atmosphere will lessen the magnitude and rate of climate change. As the United Nations Framework Convention on Climate Change (UNFCCC) recognises, a lack of full scientific certainty about some aspects of climate change is not a reason for delaying an immediate response that will, at a reasonable cost, prevent dangerous anthropogenic interference with the climate system.
As nations and economies develop over the next 25 years, world primary energy demand is estimated to increase by almost 60%. Fossil fuels, which are responsible for the majority of carbon dioxide emissions produced by human activities, provide valuable resources for many nations and are projected to provide 85% of this demand (IEA 2004)3. Minimising the amount of this carbon dioxide reaching the atmosphere presents a huge challenge. There are many potentially cost-effective technological options that could contribute to stabilising greenhouse gas concentrations. These are at various stages of research and development. However barriers to their broad deployment still need to be overcome.
Carbon dioxide can remain in the atmosphere for many decades. Even with possible lowered emission rates we will be experiencing the impacts of climate change throughout the 21st century and beyond. Failure to implement significant reductions in net greenhouse gas emissions now, will make the job much harder in the future.
Prepare for the consequences of climate change
Major parts of the climate system respond slowly to changes in greenhouse gas concentrations. Even if greenhouse gas emissions were stabilised instantly at today’s levels, the climate would still continue to change as it adapts to the increased emission of recent decades. Further changes in climate are therefore unavoidable. Nations must prepare for them.
The projected changes in climate will have both beneficial and adverse effects at the regional level, for example on water resources, agriculture, natural ecosystems and human health. The larger and faster the changes in climate, the more likely it is that adverse effects will dominate. Increasing temperatures are likely to increase the frequency and severity of weather events such as heat waves and heavy rainfall. Increasing temperatures could lead to large-scale effects such as melting of large ice sheets (with major impacts on low-lying regions throughout the world). The IPCC estimates that the combined effects of ice melting and sea water expansion from ocean warming are projected to cause the global mean sea-level to rise by between 0.1 and 0.9 metres between 1990 and 2100. In Bangladesh alone, a 0.5 metre sea-level rise would place about 6 million people at risk from flooding.
Developing nations that lack the infrastructure or resources to respond to the impacts of climate change will be particularly affected. It is clear that many of the world’s poorest people are likely to suffer the most from climate change. Long-term global efforts to create a more healthy, prosperous and sustainable world may be severely hindered by changes in the climate.
The task of devising and implementing strategies to adapt to the consequences of climate change will require worldwide collaborative inputs from a wide range of experts, including physical and natural scientists, engineers, social scientists, medical scientists, those in the humanities, business leaders and economists.
Conclusion
We urge all nations, in the line with the UNFCCC principles4, to take prompt action to reduce the causes of climate change, adapt to its impacts and ensure that the issue is included in all relevant national and international strategies. As national science academies, we commit to working with governments to help develop and implement the national and international response to the challenge of climate change.
G8 nations have been responsible for much of the past greenhouse gas emissions. As parties to the UNFCCC, G8 nations are committed to showing leadership in addressing climate change and assisting developing nations to meet the challenges of adaptation and mitigation.
We call on world leaders, including those meeting at the Gleneagles G8 Summit in July 2005, to:
Acknowledge that the threat of climate change is clear and increasing.
Launch an international study5 to explore scientifically informed targets for atmospheric greenhouse gas concentrations, and their associated emissions scenarios, that will enable nations to avoid impacts deemed unacceptable.
Identify cost-effective steps that can be taken now to contribute to substantial and long-term reduction in net global greenhouse gas emissions. Recognise that delayed action will increase the risk of adverse environmental effects and will likely incur a greater cost.
Work with developing nations to build a scientific and technological capacity best suited to their circumstances, enabling them to develop innovative solutions to mitigate and adapt to the adverse effects of climate change, while explicitly recognising their legitimate development rights.
Show leadership in developing and deploying clean energy technologies and approaches to energy efficiency, and share this knowledge with all other nations.
Mobilise the science and technology community to enhance research and development efforts, which can better inform climate change decisions.
Notes and references
1. This statement concentrates on climate change associated with global warming. We use the UNFCCC definition of climate change, which is ‘a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods’.
2. IPCC (2001). Third Assessment Report. We recognise the international scientific consensus of the Intergovernmental Panel on Climate Change (IPCC).
3. IEA (2004). World Energy Outlook 4. Although long-term projections of future world energy demand and supply are highly uncertain, the World Energy Outlook produced by the International Energy Agency (IEA) is a useful source of information about possible future energy scenarios.
4. With special emphasis on the first principle of the UNFCCC, which states: ‘The Parties should protect the climate system for the benefit of present and future generations of humankind, on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities. Accordingly, the developed country Parties should take the lead in combating climate change and the adverse effects thereof’.
5. Recognising and building on the IPCC’s ongoing work on emission scenarios.
Signed:
Academia Brasiliera de Ciências, Brazil
Royal Society of Canada, Canada
Chinese Academy of Sciences, China
Academié des Sciences, France
Deutsche Akademie der Naturforscher, Leopoldina, Germany
Indian National Science Academy, India
Accademia dei Lincei, Italy
Science Council of Japan, Japan
Russian Academy of Sciences, Russia
Royal Society, United Kingdom
National Academy of Sciences, United States of America
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the.bricoleur
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making sense of change
 
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Re:Climate change scientific consensus: It's real
« Reply #1 on: 2005-06-29 12:43:11 » |
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I guess it all hinges on how one defines ‘Climate Change’ – neat trick they just pulled there!
And no citations, what use?
Quote:| There will always be uncertainty in understanding a system as complex as the world’s climate. However there is now strong evidence that significant global warming is occurring1. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)2. This warming has already led to changes in the Earth's climate. |
Nothing new here, we have the sacred pillars of the AGW theory:
1) (a) Rising surface air temperature and (b) subsurface ocean temperature.
2) Increase in global sea levels.
3) Retreating glaciers.
4) Changes to many physical and biological systems.
5) It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)
I will address each claim in turn.
1) (a) Rising surface air temperature and subsurface ocean temperature.
Rising surface air temperature. Which weather stations were used to collect the data? This data is supposed to demonstrate a rise in the global mean temperature. How is this possible when about 32% of the earths surface is land? I am asking whether 32% is a reliable representation of the whole. I do not think so. Secondly, the majority of weather stations are situated in towns, so now we have to take into consideration the ‘urban heat island phenomenon’. In Phoenix for example, the weather station is located not only within the city but also alongside an airport (tarmac), the effect is that this station will report overnight temperatures of 10°C above the surrounding areas (due to the asphalt retaining heat). ‘Pick your stations carefully here because in doing so you will arrive at the answer you are looking for.’ See for example the work of Dr. Robert Balling (who has studied urban heat island effects in hundreds of cities throughout the United States), Director of the Laboratory of Climatology, Arizona State University, Phoenix, USA, who states, “We looked at a thousand stations in the United States that came from very small towns averaging no more than about 5,800 people. We looked at the temperature patterns over this century and found that most of the United States has cooled this century, not warmed.” He has this to say about the ‘urban heat island phenomenon’, “We've been able to detect heat islands in cities with populations as small as three hundred people. As soon as you begin to replace natural vegetation with concrete you create something of a distortion in the temperature pattern. It's an effect that can add up to two or three degrees. If we look at the issue of global warming and we ask, how much warming do we think we should see in the future, it's also something in the region of one or two or three degrees. We have to be careful when we look at people who say they have detected global warming because what they may have detected is urban warming.”
Leaving the above issues aside, what does the satellite record show us? Each snapshot of global temperature produced by analysing the satellite data is said to be the equivalent of tens of thousands of separate thermometer readings. Dr. Roy Spencer, a physicist at NASA Marshall Space Flight Centre, University of Alabama, Huntsville, has this to say about the satellite data, “We've found that we can monitor globally averaged atmosphere temperatures with a high level of precision even on a monthly basis. We estimate the precision at about one hundredth of a degree per month.” The satellite data, unlike those from weather stations, are evenly spread and do not suffer from urban heat island phenomenon.
For the period 1980-1990:
Weather stations: shows an underlying upward trend.
Satellite record: warming in the first half, cooling in the second half.
“The trend of the thermometer data is only about one to two tenths of a degree, which doesn't sound like much, but it's enough to be significantly different from the satellite indication of no trend.
Over the entire ten year period there was no net warming or cooling.”
-- Roy Spencer.
But of course whether you observe an increase depends on the time-scale selected.
Quote:| Increasing greenhouse gases are causing temperatures to rise; the Earth’s surface warmed by approximately 0.6 centigrade degrees over the twentieth century. |
A 100-year snapshot is used in this example. But if we move the time-scale what happens? Well if we take the last 50 years, we see it first goes down and then up. But more interestingly, if we take the period from 1930-1970 we see that there is a rather sharp fall in temperature. So it seems once again that the AGW theorists are choosing their time-scale to fit the required conclusions. And what if we increase our time-scale to include the Middle Ages all the way to the 20th century? Well, we get what is called the Medieval Warm Period (average temperature 2°C warmer than today) which was followed by a period referred to as the Little Ice Age. Of course the AGW theorists reject the physical evidence of these two periods in favour of a computer simulation (i.e. The Hockey Stick). The just of it is this, if we had thermometer readings going back thousands of years they would demonstrate a drop in temperature.
Before moving to point (b) subsurface ocean temperature., I would like to address the assertion that “the Earth’s surface warmed by approximately 0.6 centigrade degrees over the twentieth century” made by the article posted by rhinoceros.
Well, as far as I can see, with (all) the proxies we have three problems:
- how well those present temperature,
- how exhaustive is the global distribution of the samples, and
- how well the statistical analyses have been conducted.
Similar problems that you may notice I have already discussed in above (a). Critical and sceptical examinations have revealed failings and flaws in numerous, even peer-reviewed studies, e.g. in MBH98. My point is that the more we learn of climate the more we find that there is nothing relevant in global figures. In fact, the global view only leads astray Our globe warms and cools in different locations, unevenly and unbalanced, and is never in equilibrium. Attempts to determine global mean temperatures are meaningless - they have no practical value. Besides the practical uselessness of those statistical exercises the question of the accuracy and reliability of the instrumental record is of fundamental importance.
Please see:
GISS Surface Temperature Analysis
The Elusive Absolute Surface Air Temperature (SAT)
"For the global mean, the most trusted models produce a value of roughly 14 Celsius, i.e. 57.2 F, but it may easily be anywhere between 56 and 58 F and regionally, let alone locally, the situation is even worse." <http://data.giss.nasa.gov/gistemp/abs_temp.html>
This inaccuracy in measurements means that earth's estimated absolute global mean temperature is 14C +- 0.7C (i.e. roughly between 56F and 58F). Using computerised statistical methods the earth has been calculated to have warmed approximately 0.6 C +- 0.2C (about 1.1F) since 1880. To put it simply, with 'compelling' certainty we actually don't know whether or not the earth has warmed since 1880.
(b) subsurface ocean temperature.
Ocean warming and heat content is one of the main topics this year. We have the following studies that are probably being used as references in the original article.
Barnett, Tim P., David W. Pierce, Krishna M. AchutaRao, Peter J. Gleckler, Benjamin D. Santer, Jonathan M. Gregory, and Warren M. Washington, 2005. Penetration of Human-Induced Warming into the World's Oceans. Science Exp., published online June 2, 2005
Hansen, James E. et al., 2005. Earth's energy imbalance: Confirmation and implications.
Science Exp. April 28, 2005, and now Science Vol. 308, No 5727, pp. 1431-1435, June 3,
2005, online <http://pubs.giss.nasa.gov/docs/2005/2005_HansenNazarenkoR.pdf>
"The evidence-based on computer models and observations in the field-is so strong that it should put to an end any debate about whether human-caused global warming is a real phenomenon"
-- Tim Barnett
"Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols among other forcings, calculates that Earth is now absorbing 0.85 ± 0.15 W/m2 more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years."
-- Hansen et al
The Tim Barnett study cites evidence from computer models (!) and from observations (which probably meant "Look at this! It's what the computer model said we'd find."). I find it incredible that science has ceased to be experiment, observation and a rational assessment of the alternative possible causes. Science is now whatever the computer model tells us! All one need do in order to see the absurdity of this study is follow reasoning based on the simple physical rule that energy cannot be created nor destroyed within our atmosphere-ocean system.
Please see my comments regarding ocean warming in the following thread, New proof that man has caused global warming.
2) Increase in global sea levels.
The Oceanographic Institute near Cape Cod is considered to be one of the most influential organisations studying the sea. For many years Dr Aubrey, who heads coastal research at the Institute, has travelled the globe investigating changes in sea level. Ths is what he has to say about the matter (emphasis mine), “No, you can't say unambiguously say exactly how much the ocean has risen over the entire globe. Some tide gauge stations show sea level rising over long periods of time, others show sea level falling.
The problem is that the land is also moving up and down - in some places it subsides fairly fast. You are therefore measuring sea level against another level which is also moving up and down so you are left with a lot of uncertainty.
If you look at the British Isles you see the same thing in a small portion: in the northern part of the British Isles the sea level is falling, in the southern part the sea level is rising.
People have taken the average from different stations and different periods and come up with different answers. In effect, you can come up with any answer you want.
No useful conclusions about the future can be drawn from the record.”
Of course the AGW group then move on to assert that the sea-level rise has “accelerated” as a result of, you guessed it, human activity.
This is what Dr. Aubrey has to say about the evidence:
“There is no evidence that sea level rise has accelerated due to global warming.”
Please see the following study:
White, Neil J., John A. Church, and Jonathan M. Gregory, 2005. Coastal and global averaged sea level rise for 1950 to 2000. Geophys. Res. Lett., 32, L01601, doi:10.1029/2004GL021391, January 5, 2005
Abstract
"We compare estimates of coastal and global averaged sea level for 1950 to 2000. During the 1990s and around 1970, we find coastal sea level is rising faster than the global average but that it rises slower than the global average during the late 1970s and late 1980s. The differences are largely a result of sampling the time-varying geographical distribution of sea level rise along a coastline which is more convoluted in some regions than others. More rapid coastal rise corresponds to La Niña-like conditions in the tropical Pacific Ocean and a slower rate corresponds to El Niño-like conditions. Over the 51 year period, there is no significant difference in the rates of coastal and global averaged sea level rise, as found in climate model simulations of the 20th century. The best estimate of both global average and coastal sea level rise remains 1.8 ± 0.3 mm yr?1, as found in earlier studies."
............
White et al (2005) do not question the reality of a minute "global average and coastal sea level rise of 1.8 ± 0.3 mm yr-1"; although they stress that this has been intermittent during the last 50 years. What their findings do question, however, is that the alleged doubling of ice loss as a result of "unprecedented" warming during the last 15-20 years has had any measurable effect on coastal or global sea levels (confirming what many other studies have demonstrated before). The implications seem obvious to me: Whatever the warming during the last 50 years may have been, it has had no significant effect on sea levels fluctuation.
Once again, empirical data based on concrete observations have falsified climate models that have been predicting an accelerated rise of sea levels due to 'unprecedented' and 'disastrous' global warming.
3) Retreating glaciers.
Please see the following study:
Kaser, Georg, Douglas R. Hardy, Thomas Mölg, Raymond S. Bradley and Tharsis M. Hyera, 2004. Modern glacier retreat on Kilimanjaro as evidence of climate change: observations and facts. International Journal of Climatology Vol. 24, No 3, pp. 329-339, March 2, 2004. (NOTE: I am not permitted to supply this URL by the BBS – I keep getting a false positive for illegal HTML tags – a google search should suffice.)
Abstract
In recent years, Kilimanjaro and its vanishing glaciers have become an icon of global warming, attracting broad interest. In this paper, a synopsis of (a) field observations made by the authors and (b) climatic data as reported in the literature (proxy and long-term instrumental data) is presented to develop a new concept for investigating the retreat of Kilimanjaro's glaciers, based on the physical understanding of glacier-climate interactions. The concept considers the peculiarities of the mountain and implies that climatological processes other than air temperature control the ice recession in a direct manner. A drastic drop in atmospheric moisture at the end of the 19th century and the ensuing drier climatic conditions are likely forcing glacier retreat on Kilimanjaro. Future investigations using the concept as a governing hypothesis will require research at different climatological scales.
6. CONCLUSIONS AND DIRECTION FOR FUTURE RESEARCH
Under present climate conditions, glaciers on Kibo continue to retreat, and it appears likely that by mid-century the plateau glaciers will disappear from the mountain for the first time in over 11000 years. Still, there are several open questions to be answered in future investigations. How and when has the glaciation reached a maximum extent, of which today’s remnants are the matter of both scientific and public concern?
How did local convection on the mountain slopes and regional advection work, in order to allow sufficient moisture transport to the summit of Kibo for the formation of glaciers? How did the East African or even the large-scale vertical structure of the tropical troposphere differ? Has the Indian Ocean played a role different from today? How different was the atmospheric circulation over East Africa, and was this only a regional peculiarity? To find a way in this complex web of questions, future research must span different scales: from the microscale when detecting the processes at the glacier–atmosphere interface, to the mesoscale when simulating the circulation on the mountain slopes and over East Africa, and can even reach the global scale when providing information that can be considered in general circulation climate models. Such research is currently in progress as a collaborative effort between Innsbruck and Massachusetts universities, using the concept presented here as a working hypothesis.
Two studies within this collaborative project have been conducted in the meantime (Molg et al., 2003b; Molg and Hardy, 2004) and provide a first detailed support for the microscale part of the hypothesis derived in this article. Molg et al. (2003b) illustrate that solar-radiation-driven melting controls vertical ice wall retreat, given the generally dry climate with a lack of accumulation on glaciers. Their results verify the concept for ice wall retreat depicted in Figure 4. Further, Molg and Hardy (2004) show that mass loss on the summit horizontal glacier surfaces is mainly due to sublimation i.e. turbulent latent heat flux, and is little affected by air temperature through the turbulent sensible heat flux - both aspects that support the interpretations made in the first item of Section 4. However, validation and verification of the entire hypothesis presented in this paper will require additional meteorological measurements and experiments, and mesoscale modelling of atmospheric dynamics over Kilimanjaro.
See also:
Rignot, Eric et al., 2003. Contribution of the Patagonia Icefields of South America to Sea Level Rise. Science Vol. 302, No 5644, pp. 434-437, October 17, 2003
Digital elevation models of the Northern and Southern Patagonia Icefields of South America generated from the 2000 Shuttle Radar Topography Mission were compared with earlier cartography to estimate the volume change of the largest 63 glaciers. During the period 1968/1975–2000, these glaciers lost ice at a rate equivalent to a sea level rise of 0.042 +- 0.002 millimeters per year. In the more recent years 1995–2000, average ice thinning rates have more than doubled to an equivalent sea level rise of 0.105 +- 0.011 millimeters per year. The glaciers are thinning more quickly than can be explained by warmer air temperatures and decreased precipitation, and their contribution to sea level per unit area is larger than that of Alaska glaciers.
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Well, it seems that glaciers retreat and melt on their own, despite short-time climate temperature fluctuations, and as one climatologist stated, “glaciers are not thermometers.” These new studies, among others, confirm that glaciers are not the alleged icons of anthropogenic global warming.
Of course this does, with point 2 above, kill the AGW theorists simplistic equation of anthropogenic global warming = melting glaciers = rising sea levels = disaster and doom for all mankind.
I want to use some time here to discuss glaciers to sea level (SL) rise.
Referring to the IPCC TAR, Table 11.14 – it gives an indication of the contributions of glaciers to sea level (SL) rise, and for that there are many positive estimates. It is this net effect to which they conclude that collectively, glaciers worldwide are receding.
The IPCC has many positive estimates of the contribution of glaciers to SL rise. Unfortunately, these estimates have been made, to quote from the IPCC, from "AOGCM experiments following the IS92a scenario", which does not lend them much credence right from the start. But setting aside their dubious provenance for the moment, this claim faces four very large problems.
The first is that there is no data that I am aware of indicating any recent acceleration in historical rates of mean sea level (MSL) rise. In fact, the opposite is true ... An important finding of Mitchell et al (1) is that the Pacific does not exhibit any change in the historical rate of MSL rise. The advantage of the asymptotic analysis method used by Mitchell is that it would show any recent increase in the rate of MSL rise, such as that predicted to occur with increasing temperatures. However, it shows no such change.
To quote from the Mitchell et al study, "It will be acknowledged, nevertheless that visually at least, and at this stage, there is no clear evidence for an acceleration in sea level trends over the course of the last century. Personnel familiar with sea level work were cautious to accept the findings of the early numerical climate models, which triggered much of the anxiety among coastal dwellers over the last two decades. These models forecast rapidly accelerating sea level trends. The hard facts of sea level observations identified here, serve to confirm a more moderate view of sea level trends." In other words, there is no evidence that in the Pacific the rate of MSL rise has changed from the historical norm. This lack of change in the historical rate of MSL rise is further confirmed by a recent study (2) of the sea levels in New Zealand, which concludes "There continues to be no evidence of any acceleration in relative sea levels over the record period."
Here is a graphic showing some of the longest-term sea level records that we have, from the PSMSL (Permanent Service for the Mean Sea Level). As you can see, none of these records shows any recent increase above the historical rate of MSL rise, and some, like Bombay and Sydney, show that the rate has decreased.
http://www.pol.ac.uk/psmsl/anomalies/1980-1990.1930-1970.gif
The IPCC TAR agrees that there has been no rise in the rate of increase of MSL, saying, "The tide gauge data for the 20th century show no significant acceleration (e.g., Douglas, 1992)."
SOURCE: http://www.grida.no/climate/ipcc_tar/wg1/428.htm
If, as the IPCC claim, the contribution from glaciers is large enough to be visible in the record, we should have seen some acceleration from the claimed increase in glacier melt over the 20th century.
The second problem is that the range of estimates of the contribution of glacier melt to sea level rise is so wide as to make them unusable. The estimates range from 10 mm per century (so small as to be undistinguishable from noise) to 230 mm per century (20% larger than the largest rise in the chart above!). Surely this wide range precludes us from using this as evidence that the glaciers are melting.
Third, these estimates of the contribution of glacier melt to sea level rise are not based on data. In other words, they did not come from scientists saying, "The glaciers have shrunk this much, so that much water has been added to the ocean." They come from AOGCMs, which are scientists saying "If we had so many glaciers in 1900, and the temperature went up this much, that much water would melt from the glaciers into the ocean." Because they are not based on data but on an assumption that glaciers are melting, using them to support your argument that glaciers are melting is circular.
Fourth, these same AOGCMs, when given the conditions of 1900, utterly fail to reproduce even the gross attributes of the temperature swings of the 20th century (rising until 1930, falling until 1970, rising since then). Why should we place even the smallest credence in what they have to say about glacier melting?
The IPCC, by the way, gets out of the problem of the lack of acceleration in the 20th century rise in MSL in their usual ingenious way ... they say that the rate of change of MSL is actually dropping (3), and this is being compensated for by the glacial melt. Bad scientists, no cookies ...
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REFERENCES
1) Mitchell, W., Chittleborough, J., Ronai, B., and Lennon, G. W., Sea Level Rise in Australia and the Pacific, Australian National Tidal Facility (NTF),
http://www.ntf.flinders.edu.au/TEXT/CONF/cook2000/papers/Mitchell2.pdf
2) Hannah, J., 2004. An updated analysis of long-term sea level change in New Zealand, Geophys. Res. Lett., 31, February 12, 2004
http://www.agu.org/journals/gl/gl0403/2003GL019166/2003GL019166.pdf
3) To quote from the IPCC, "If the terrestrial storage terms have a negative sum (Section 11.2.5), they may offset some of the acceleration in recent decades." ...
SOURCE: http://www.grida.no/climate/ipcc_tar/wg1/428.htm
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4) Changes to many physical and biological systems.
What to say? “Hey, look at that change!” “Hmm you know we are more likely to get funding to study this change if we suggest it is due to global warming.” “Good idea.”
5) It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)
The IPCC does not consider water vapour to be a ‘greenhouse gas’ but rather ‘feedback’ (no climate forcing). The IPCC models use various ‘feedback’ assumptions but there are no actual observations to confirm them. How can we possibly believe the models? We can’t.
-- The IPCC asserts that all climate change is induced by alteration to radiative forcing.
-- Change to concentrations of greenhouse gases in the atmosphere alters radiative forcing.
-- Water is a greenhouse gas (it causes most of the radiative greenhouse effect) but its concentration in the atmosphere is assumed to be a function of temperature*** (warmer means more evaporation, colder means more precipitation).
-- If greenhouse gases other than water vapour increase their concentrations then that increases the temperature.
-- The higher temperature puts more water vapour into the air and this increase to water vapour (a greenhouse gas) raises the temperature further (this is called the 'water vapour feedback').
-- Hence, for its purposes, the IPCC defines water vapour as a 'feedback', and not a 'greenhouse gas'.
It is important to note that the definition of water vapour as a 'feedback' derives from an unproven assumption; viz. *** The concentration of water vapour in the atmosphere is assumed to be a solely function of temperature.
This assumption that water vapour concentration in the atmosphere is solely a function of temperature is only true if the atmosphere is saturated. The atmosphere is not saturated and so the assumption is false.
The concentration of water vapour in the atmosphere is a function of the difference between the globally averaged evapotranspiration (the water vapour source to the atmosphere) and the globally averaged precipitation (the water vapour sink). The former is linked to the vapour pressure difference between the terrestrial and ocean surfaces and that of the atmosphere. Of course the saturated vapour pressure of the terrestrial and ocean surfaces is assumed to be a function of temperature but the vapour pressure of the atmosphere is a function also of humidity, which may be low (over the deserts and subsiding air masses) or high (regions of surface air convergence). Precipitation is a function of atmospheric dynamics and increases with overturning air and decreases with stable air. It seems to me that even the assumption of constant atmospheric humidity is drawing a rather long bow! Water vapour feedback looks like a contrived feedback mechanism.
One should also be cognisant that evapotranspiration and precipitation are essential components of the energy cycle. Evapotranspiration takes excess energy from the underlying earth surface (without raising the temperature) and precipitation makes that energy available to the atmosphere to offset net radiation cooling. To a large extent, the atmospheric water vapour is an outcome of the energy cycle, not a driver, as the feedback mechanism would suggest.
The greenhouse gases are supposed to operate by absorbing infrared radiation from the earth - the most important of these is water vapour, then comes carbon dioxide. It is claimed that the total "greenhouse effect" is increasing because of human activity.
One would think that the first thing to look at would be to study any changes in atmospheric concentration and distribution of water vapour. But it is very difficult and there is virtually no information. So claims for "global warming" cannot be substantiated from its major component.
But JUST STOP ... The second most important greenhouse gas can be measured, and it can be shown to be increasing. But this is only a minor effect. Thus the only thing to do is to claim that water vapour can be rigidly determined from carbon dioxide concentration. Instead of measuring it you can use a mathematical equation and call it "feedback". But there is no evidence for any such theoretical assumption from sufficiently widespread measurements in the atmosphere. A cop-out.
The same applies with clouds. It is quite illogical that one sort of cloud is a "feedback" and another, the extra clouds caused by some indirect effects is classified as a "forcing". The only reason for the difference is that you can give some sort of plausible figure for the second kind of cloud, whereas there are no useful historic measurements of clouds. So, again, the IPCC assume a purely theoretical relationship with carbon dioxide and call it "feedback". Another cop-out.
The "radiative forcing" figures published by the IPCC are dubious enough, with their "error bars" that "have no statistical significance" and the supposed "levels of scientific understanding". The whole business would collapse in disarray if they had to make a stab at changes in water vapour, clouds, or the "warm cloud indirect effect" as well, so let us relegate them to "feedbacks" and claim they do not matter.
The IPCC explains its concept of radiative forcing by way of the annual and global mean energy balance (Figure 1.2, p 90 of the TAR). This is the flat earth radiation model because it only treats one dimension, the vertical, and ignores the motions of the atmosphere and oceans. But it does indicate that 67 W/m-2 of the total solar radiation component of 342 W/m-2 are absorbed by the atmosphere. Some might say that this is a “warming component”. However, if we look at all of the radiation components we note that the net effect of radiation is to cool the atmospheric layer at a rate of 102 W/m-2. Now this is very curious. How do greenhouse gases warm the earth's surface if the atmosphere is continuously cooling because of radiation loss, especially the loss of longwave radiation?
Of course, the answer lies in the fact that the climate system is a little more complex than the one-dimensional flat earth radiation model allows. In particular, energy balance in the atmospheric layer requires evaporation and heat conduction from the underlying terrestrial and ocean surfaces and the latter varies with the surface temperature. The underlying surface temperature of the earth is largely a function of the absorbed solar radiation and the effective thermal capacity of the underlying surface. We should note that, as far as the underlying surface is concerned, greenhouse gases reduce the net loss of longwave radiation but the source of energy is still solar radiation.
By adding one additional level of realism to the IPCC's simple one-dimensional flat earth model of the energy budget we add complexity. We see that the earth's surface temperature (not to be confused with the near surface temperature of the atmosphere) will vary with the greenhouse gas concentration (the longwave emission of the atmospheric layer), the intensity of solar radiation and the effective thermal capacity of the earth's surface. As 70 percent of the earth's surface is made up of oceans in motion it would be a brave scientist who would argue that the effective thermal capacity of the earth is a constant. And yet this is what IPCC does when it argues for its simple radiation model and the claim of limited internal variability of the climate system!
"The Term 'radiative forcing' has been employed by the IPCC Assessments to denote an externally imposed perturbation in the radiative energy budget of the Earth's climate system. Such a perturbation in the radiative energy budget can be brought about by secular changes in the concentrations of radiatively active species (e.g. CO2, aerosols), changes in solar irradiance incident upon the planet, or other changes that affect the radiative energy absorbed by the surface (e.g. changes in surface reflection properties).”
-- from IPCC page 353 of "Climate Change 2001" paragraph 6.1
The key IPCC Figures 3 (page 8), 9 (page 37) and 6.6 (page 392) which give such dubious estimates of global and annual mean radiative forcing (1750 to present) include "Solar" (but exclude "water vapour").
The point is, that any "climate change" that is supposed to be taking place, is thought to be related to the total radiative forcing, not just to that part of it which can be attributed to the greenhouse effect. Any questions relating to absorption of solar radiation by water vapour are entirely relevant to possible changes in radiative forcing and therefore to climate, but are dismissed by the IPCC/anthropogenic global warming theorists for reasons that I have hopefully clarified here.
Oh and did I mention that the ice core record shows atmospheric CO2 varying in concert with but after temperature changes?
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To conclude:
"there is now strong evidence that significant global warming is occurring"
BULLSHIT
-- Iolo
I notice that I have been hasty in posting this, as there are parts of the reply that I have failed to reference. I’ll return ASAP to rectify. Apologies.
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