<p>Stick to the facts: In a regional chapter on Asia in Working Group 2 (climate impacts) of the 4th IPCC report, written by authors from the region, it was erroneously stated that 80% of Himalayan glacier area would very likely be gone by 2035. This was of course not the proper IPCC projection of future glacier decline, which is found in the Working Group 1 report (which is the one about basic climate science, including the future projections of climate change). There we find a 45-page, perfectly valid chapter on glaciers, snow and ice (Chapter 4), with the authors including leading glacier experts (such as my good colleague Georg Kaser from Austria, who first discovered the Himalaya error in the WG2 report). There are also several pages on future glacier decline in Chapter 10 (“Global Climate Projections”), where the proper projections are used e.g. to estimate future sea level rise. So the problem here is not that the IPCC’s glacier experts made an incorrect prediction. The problem is that a WG2 chapter, instead of relying on the proper IPCC projections from their WG1 colleagues, cited an unreliable outside source in one place. Fixing this error involves deleting two sentences on page 493 of the WG2 report. This was an unfortunate citation error by the WG2 colleagues from Asia, but it was not based on an incorrect prediction by the IPCC climate scientists, as you well know.</p>
<p>Stick to the facts: the IPCC does in fact give as its best estimate all of the warming since 1950 is caused by humans. The natural contributions are estimated to be about zero and constrained to be within -0.1 and +0.1 °C for both internal and externally forced natural variability. That is why the IPCC writes in the Summary for Policy Makers (available at www.ipcc.ch): "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century." I wonder why you keep downplaying the serious risk that global warming poses to human civilisation, even to the extent of distorting to your readers what the IPCC (i.e. the scientific community at large) finds.</p>
Your claim is simply wrong. The IPCC does not claim that *all* warming is due to humans. They say it is above 50%. This is *exactly* why they say "human influence has been the dominant cause of the observed warming since the mid-20th century." (Dominant meaning more than half the cause.) If they believed that humans were the full reason, they would have written 'human influence is the only cause of the observed warming since the mid-20th century.' Pls don't misrepresent the science.
If you want, you can read the IPCC summary, where they actually explain what they mean with 'dominant' in the very next sentence: "It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together."
"More than half" -- not all of it. Or as I wrote: "humans have caused more than half of the global rise in temperature since 1950."
<p>Stick to the facts: the IPCC writes about sea level in its Summary for Policy Makers (available at www.ipcc.ch): "For RCP8.5, the rise by the year 2100 is 0.52 to 0.98 m". (RCP8.5 is a scenario with unmitigated rise in greenhouse gas emissions.) For the lowest emissions scenario RCP2.6 (which involves drastic emissions reductions starting in a few years and leading to zero global emissions by 2070, after that active removal of CO2 from the atmosphere) the best estimate sea-level rise by the year 2100 given by IPCC is 44 cm. </p>
Dear Kir, I checked this, and think you mixed up Mike Mann with Phil Jones, about whom "climate skeptics" indeed made such claims. They are bogus, though: this was about the weather observations that go into the CRU global temperature series, and these primary data of course come from the weather services of the various countries, who are charged with collecting and archiving them. An overview over this and other myths and falsehoods spread by "climate skeptics" was compiled by the media watchdog organisation Media Matter for America here: http://mediamatters.org/research/2010/04/06/myths-and-falsehoods-from-the-assault-on-global/162783#myth6
Dear Kir, we know that the anthropogenic increase in greenhouse gases in the atmosphere is by far the dominant climate forcing over the last hundred years. The increase in CO2 to date causes a climate forcing of 2 Watts per square meter of Earth's surface. Compare this e.g. to solar variations, which have a peak forcing (difference between solar max and solar min) of only 0.2 Watts per square meter. (And this is a cycle, not a trend.) All forcings, natural and anthropogenic, are always compared in one of the very first diagrams in the IPCC reports - have a look at the upcoming one as soon it is published, or at the last one, you find them online at www.ipcc.ch.
Your statement about destroyed primary data is bizarre - where did you get that from? The primary paleoclimate data used in the hockey stick are available here: http://www.meteo.psu.edu/holocene/public_html/shared/research/MANNETAL98/
A list of many further data sources is found on the Realclimate website here: http://www.realclimate.org/index.php/data-sources/
NASA maintains a nice overview site with key climate indicators (CO2, temperature, sea level, sea ice , land ice): http://climate.nasa.gov/key_indicators/
There is probably no field of science were so many data (and computer codes for their analysis) are freely available to everyone as in climate research. (Or do economists lay open their data and model codes?) Don't get confused by the political propaganda found in some media. All the information you need is available freely from reputable scientific sources.