Key findings of UN scientific report (UN Intergovernmental Panel on Climate Change - IPCC)

AP on Yahoo ^ | 11/17/07 | AP

[NormsRevenge]

The following are some key findings in a report issued Saturday by the United Nations Intergovernmental Panel on Climate Change:

• Global warming is "unequivocal." Temperatures have risen 1.3 degrees Fahrenheit in the last 100 years. Eleven of the last 12 years are among the warmest since 1850. Sea levels have gone up by an average seven-hundredths of an inch per year since 1961.

• About 20 percent to 30 percent of all plant and animal species face the risk of extinction if temperatures increase by 2.7 degrees Fahrenheit. If the thermometer rises by 6.3 degrees Fahrenheit, between 40 to 70 percent of species could disappear.

• Human activity is largely responsible for warming. Global emissions of greenhouse gases grew 70 percent from 1970 to 2004. The concentration of carbon dioxide in the atmosphere is far higher than the natural range over the last 650,000 years.

• Climate change will affect poor countries most, but will be felt everywhere. By 2020, 75 million to 250 million people in Africa will suffer water shortages, residents of Asia's large cities will be at great risk of river and coastal flooding, Europeans can expect extensive species loss, and North Americans will experience longer and hotter heat waves and greater competition for water.

• Extreme weather conditions will be more common. Tropical storms will be more frequent and intense. Heat waves and heavy rains will affect some areas, raising the risk of wildfires and the spread of diseases. Elsewhere, drought will degrade cropland and spoil the quality of water sources. Rising sea levels will increase flooding and salination of fresh water and threaten coastal cities.

• Even if greenhouse gases are stabilized, the Earth will keep warming and sea levels rising. More pollution could bring "abrupt and irreversible" changes, such as the loss of ice sheets in the poles, and a corresponding rise in sea levels by several yards.

_A wide array of tools exist, or will soon be available, to adapt to climate change and reduce its potential effects. One is to put a price on carbon emissions.

• By 2050, stabilizing emissions would slow the average annual global economic growth by less than 0.12 percent. The longer action is delayed, the more it will cost.

[cogitator]

One hundred years ago, ships typically lowered a bucket in the sea and then measured the temp once brought back onboard; how has the measurement technique changed since?

Most ships currently measure the temperature of the surface intake water. But now there is also an increasing number of drifters returning both subsurface and surface temperatures via satellite uplink.

There are a number of references available evaluating the techniques, constructing time-series based on various methodologies, corrections, etc.

[Old Professer]

Are there any links to the collected data points and their paths or timeline of locations sampled?

[boop]

"The NASA corrections were for U.S. temperatures."

Now I'm really confused. So Nasa's data that they just changed said the hottest years in a century were in the 1930's ONLY in the US? I had no idea there was isolated heating in only one country.

[milwguy]

The IPCC probably left out NASA’s REVISED figures because they did not fit the ‘consensus’. Just like Mann’s famous hockey stick graph, which in an earlier IPCC report was the ‘proof’ they relied on to foist the Global Warming charade upon the unsuspecting citizenry of the world. Of course you won’t find Mann’s graph ANYWHERE in the new report because it was shown to be a FRAUD.

[cogitator]

Two things. One, hurricanes are exciting and noticeable and can be devastating and horrible, and they are also unusual and variable climate phenomena which require a specific set of factors to form and to persist/strengthen. Some of these factors are likely strongly related to global warming, others less so, some not at all. Thus, I find it pointless to evaluate global warming projections on the basis of regional frequencies and intensities. So I don't. I will let you find comfort in short-term variable statistics.

Two, the period you are addressing regarding Greenland is commonly referred to as the "Holocene Climate Optimum", and it is generally considered to have been warmer than present. Feel free to research it. The HCO has intrigued me a bit. Here are a couple of items about it.

Mid-Holocene Warm Period - About 6,000 Years Ago

From the above: "These orbital changes can be easily calculated and predict that the northern hemisphere should have been warmer than today during the mid-Holocene in the summer AND colder in the winter. The paleoclimatic data for the mid-Holocene shows these expected changes, however, there is no evidence to show that the average annual mid-Holocene temperature was warmer than today's temperatures."

But, imporantly, what about the Greeland ice cap? I worked quite a bit on this, but I couldn't find anything directly addressing what happened to the Greenland ice cap during the HCO. But I did find this little item:

Early Holocene Climate Variability and the Timing and Extent of the Holocene Thermal Maximum (HTM): Comparisons From the Northern and Southern Hemispheres I Posters

Poster entitled: Diatoms as Proxies for a Fluctuating Ice Cap Margin, Hvitarvatn, Iceland.

Abstract: There are no complete records of terrestrial environmental change for the Holocene (11,000yrs) in Iceland and the status of Icelandic glaciers in the early Holocene remains unclear. It is not even known whether Iceland's large ice caps disappeared in the early Holocene, and if they did, when they re-grew. Icelandic lakes are particularly well suited to address these uncertainties as: 1) Glacial erosion and soft bedrock result in high lacustrine sedimentation rates, 2) Diagnostic tephras aid the geochronology, 3) Iceland's sensitivity to changes in North Atlantic circulation should produce clear signals in key environmental proxies (diatoms) preserved in lacustrine sequences, and 4) Ice-cap profiles are relatively flat so small changes in the equilibrium line altitude result in large changes in accumulation area. Hence, large changes in ice-sheet margins during the Holocene will impact sedimentation in glacier-dominated lakes and the diatom assemblages at those times. Hvitarvatn is a glacier dominated lake located on the eastern margin of Langjokull Ice Cap in central-western Iceland. The uppermost Hvitarvatn sediments reflect a glacially dominated system with planktonic, silica-demanding diatom taxa that suggest a high dissolved silica and turbid water environment consistent with high fluxes of glacial flour. Below this are Neoglacial sediments deposited when Langjokull was active, but outlet glaciers were not in contact with Hvitarvatn. The diatom assemblage here shows a small increase in abundance, but is still dominated by planktic, silica-demanding taxa. A distinct shift in lake conditions is reflected in the lowermost sediments, composed of predominantly benthic diatoms and deposited in clear water conditions with long growing seasons likely found in an environment with warmer summers than present and with no glacial erosion. Langjokull must have disappeared in the early Holocene for such a diverse, benthic dominated diatom assemblage to flourish.

This map shows where Langjokull is and how big it is, approximately, now:

And finally I found this recent item:

Understanding Greenland Ice Sheet Response To Global Warming

You can read that if you want.

[cogitator]

So Nasa's data that they just changed said the hottest years in a century were in the 1930's ONLY in the US?

This was confusing (and it wasn't helped by inaccurate media reports). I wrote this to try and help FR to sort it out:

A little perspective on the U.S. and global temperature records

[cogitator]

I went back and checked that, and for some reason after I wrote it the global record image disappeared. I’m going to put it back at the current end of that thread.

[cogitator]

Sorry! I realized that I had done an update. See post 69 in the thread linked in post 67 of THIS thread.

[milwguy]

‘The field data will be used as a basis for modelled projections of future change in Arctic regions (e.g., Greenland ice sheet contribution to global sea level and impact on thermohaline circulation) which have socio-economic implications, both for the Arctic regions and more widely (Themes 5 and 6).’........................ ANY modelling is inherently subject to the data which is used as input. Any climatologist worth his salt will admit the complexities of our climate are far too complicated to be accurately modelled. We are in the infancy of climatology, and have no idea how water vapor, cirrus clouds, solar activity, and a million other variables play into the overall climate change and how much role each of these thousands of variables play. I saw this week that the circulation in the Arctic is reversing, what model predicted that? What will it’s affects be on the extent of Arctic sea ice in future years? .................Not too long ago in geologic terms, where I am typing was covered in 1/2 mile thick ice sheet. What caused it to disappear? The glaciers retreating in Greenland are exposing tree roots mere 1000’s of years old, which means not too long ago trees were growing where the glaciers are now retreating from, which means not too long ago the Glaciaers were NOT there. As for hurricanes, my use of them merely illustrates the limits of modelling, for the best meteorologists in the world used them to predict EACH hurricane season, and for the last two years they have been DEAD wrong. How can we take at face value what ‘experts’ tell us will happen in 100 years if we can’t trust their preditions for the next year’s hurricane season, or even next months weather?