The Intergovernmental Panel on Climate Change (IPCC) has released a draft summary of its upcoming report on climate change, and the media are hyping the scary scenarios.  Typical is the headline in the Arizona Daily Star: “Scientists: More weather crises are on their way.”

If you think about it a minute, that headline is  equivalent to this: “Scientists predict sun will rise tomorrow.”  Of course we have had and will continue to have weather extremes.

The headline is all too familiar.  Here is another headline from the New York Times:”Scientists Say Earth’s Warming Could Set Off Wide Disruptions.”  That headline was from September 18, 1995.

In the 1995 article, the IPCC made some predictions, one of which we can now test.  They predicted: “A striking retreat of mountain glaciers around the world, accompanied in the Northern Hemisphere by a shrinking snow cover in winter.”

It so happens that the Rutgers University Global Snow Lab keeps track of snow cover. The graph below shows that rather than a  decrease, snow cover in the Northern Hemisphere has been increasing since 1995:

 

 

 

 

 

 

 

 

 

 

 

 

 

We can also look at extreme high and low temperatures.  The National Climate Data Center has a map and table here, which shows that for each state, most of the extreme high and low temperatures occurred before 1950.  Of the 50 states, 29 had record lows and 35 had record highs prior to 1950.

We can also look at the trends for precipitation, drought, and hurricanes:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The United States Geological Survey studied the relationship between floods and rising carbon dioxide.  The USGS found that for most of the country during the last 100 years, there is no strong statistical evidence for flooding increasing or decreasing with rising carbon dioxide.  In the southwest however, they found that flooding has been decreasing with rising carbon dioxide.

“To capture the public imagination, we have to offer up some scary scenarios, make simplified dramatic statements and little mention of any doubts one might have. Each of us has to decide the right balance between being effective, and being honest.” –Dr. Stephen Schneider

The IPCC has lost all credibility except to the credulous press and those with a vested interest in maintaining the carbon dioxide myth.

See also:

The Assumed Authority

Book Review: The Delinquent Teenager Who Was Mistaken for the World’s Top Climate Expert, an IPCC Exposé

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Breaking news: ice melts in summer! It’s mid-September and Arctic sea ice extent has reached its normal low point. In an alarmist story, the Arizona Daily Star reports, “Summer ice melt in Arctic growing.” The story says: “Arctic sea ice melted this summer to the second-lowest level since record-keeping began more than 50 years ago, scientists reported Thursday, mostly blaming global warming.” True enough, but so what?

The graph below shows the Arctic sea ice extent in relation to recent years.

 

 

 

 

 

 

 

 

 

 

 

 

 

Notice that the apparent turn-around has happened earlier than in recent years. What such stories almost never report is what is going on in the Antarctic. This year, the Antarctic sea ice extent is above average. The same thing happened in 2007 when the Arctic sea ice extent reached the lowest extent ever recorded by satellites. At that same time, Southern Hemisphere sea ice extent broke the previous maximum record of 16.03 million sq. km and reached 16.26 million sq. km. [Source: The Cryosphere Today, a publication of The Polar Research Group, University of Illinois]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fluctuation in the extent of Arctic sea ice is normal and not cause for alarm. According to a study from the University of Copenhagen, “For the last 10,000 years, summer sea ice in the Arctic Ocean has been far from constant. For several thousand years, there was much less sea ice in the Arctic Ocean – probably less than half of current amounts.”

The Star story says, “The summer minimum is a key measurement for scientists monitoring man-made global warming.” Maybe those scientists should look at the whole picture. There are many complicating factors in natural variation, as the Copenhagen study points out.

And, just to put things in perspective, I offer two other reports on Arctic ice:

 ”A considerable change of climate inexplicable at present to us must have taken place in the Circumpolar Regions, by which the severity of the cold that has for centuries past enclosed the seas in the high northern latitudes in an impenetrable barrier of ice has been, during the last two years, greatly abated.”

“2000 square leagues [approximately 14,000 square miles or 36,000 square kilometers] of ice with which the Greenland Seas between the latitudes of 74 and 80 N have been hitherto covered, has in the last two years entirely disappeared.” (Royal Society, London. Nov. 20, 1817. Minutes of Council, Vol. 8. pp.149-153)

 

Or this story:

Arctic Ocean Getting Warm; Seals Vanish And Icebergs Melt

 The Arctic ocean is warming up, icebergs are growing scarcer and in some places the seals are finding the waters too hot, according to a report to the Commerce Department yesterday from Consul Ifft, at Bergen, Norway .

 Reports from fishermen, seal hunters and explorers, he declared, all point to a radical change in climatic conditions and hitherto unheard-of temperatures in the Arctic zone. Exploration expeditions report that scarcely any ice has been met with as far north as 81 degrees 29 minutes. Soundings to a depth of 3,100 meters showed the gulf stream still very warm.

 Great masses of ice have been replaced by moraines of earth and stones, the report continued, while at many points well known glaciers have entirely disappeared. Very few seals and no white fish are being found in the eastern Arctic, while vast shoals of herring and smelts, which have never before ventured so far north, are being encountered in the old seal fishing grounds.

 This is from an AP story which appeared in the Washington Post, November 2, 1922.

 

It seems, therefore, that nothing out of the ordinary is happening, including the alarmists’ cry of “Wolf.”

  

For more background see:

 A Perspective on Climate Change a tutorial

 Arctic Temperatures: Not So Hot

 Arctic tipping point, will there be an ice-free Arctic

 Natural Climate Cycles

 

 

 

 

 

The headline from the University of Arizona News, and many other news outlets said, “Twentieth-Century Warming in Lake Tanganyika is Unprecedented.” The headline from Brown University press release (home of the lead author) said, “Brown Geologists Show Unprecedented Warming in Lake Tanganyika.”

Well, not exactly. The title of the study referred to is “Late-twentieth-century warming in Lake Tanganyika unprecedented since AD 500,” published in Nature Geoscience (16 May 2010). Even that more modest claim doesn’t tell the whole story.

First some background. Lake Tanganyika occurs within the East African Rift, which is a divergent tectonic plate boundary that is gradually separating East African countries from the main continent. The rift contains both active and dormant volcanoes. The lake is 418 miles long and 45 miles wide. Its average depth is 1,870 feet with a maximum depth of 4,820 feet. Portions of the lake are claimed by Burundi, Democratic Republic of the Congo, Tanzania, and Zambia. Fishing the lake provides a major food source for people in the surrounding lands. There is concern that lake warming will disrupt the fish supply.

The abstract of the paper concludes, “Our records indicate that changes in the temperature of Lake Tanganyika in the past few decades exceed previous natural variability. We conclude that these unprecedented temperatures and a corresponding decrease in productivity can be attributed to anthropogenic global warming, with potentially important implications for the Lake Tanganyika fishery.”

The questions I had upon reading this were: 1) Are the temperatures really unprecedented? 2) Do they exceed natural variability? 3) What is the evidence that the warming was caused by anthropogenic global warming? 4) Could there be some other cause of fish decline?

The researchers studied lake sediment cores going back 60,000 years and by using proxies deduced a temperature record for the lake surface temperature. In the current study, the researchers said that during the last 1,500 years, temperature varied between 22.5º C and 25.7º C, and that in the last 50 years the temperature rose by 1.6º C.

However, in 2008, these same researchers published a paper in Science (Vol. 322. no. 5899, pp. 252 – 255) which said the lake surface temperature fluctuated between 27° and 29°C over the last 60,000 years according to their interpretation of lake sediment cores.

I emailed a co-author of the paper, a UofA professor, asking for an explanation of this apparent discrepancy. He replied by referring me to the website of the lead author at Brown University. There, she explained that there was a problem in calibration of the temperature proxies. She presents a graph showing the records after recalibration. It is reproduced below. It should be noted that there are two separate core sample locations. The more recent core was taken closer to shore than the older, longer record. The more recent record initially shows cooler temperatures where the two records overlap. The researchers attribute this discrepancy to upwelling cold water from deeper in the lake. So which record is closer to the real surface temperature?

 

 

According to the lead author’s own data as shown on the graph, it is obvious that the current temperatures are not unprecedented, nor do they exceed natural variability. The title of their paper is technically correct only if one accepts cherry-picking start dates.

That leaves the question about the cause of the warming. The UofA scientist replied to my email, “our record only demonstrates a lake surface temperature history, not the cause of that history.” The allegation of an anthropogenic cause, a major conclusion of the paper, was made without any supporting evidence, just speculation.

I am wondering why the paper abstract contains the conclusions it does. Is it time for some scary scenarios to promote more study and more funding?

This whole study purports to be about lake surface temperatures, but it contains very few such measurements from the lake surface. From my reading, the researchers deduce surface temperatures from only two core sample locations. As the NOAA satellite graphic below shows, on any given day, at any given time, the variation in lake surface temperature can be as much as 4º C in different parts of the lake, and that equals or exceeds the entire range of temperatures found in the studies. It would seem, therefore, that any temperature record derived from sediment cores could vary greatly depending on location. Since this study had just two sample locations, it makes one wonder if it gives a true representation of actual conditions.

 

 

 

 

 

And about the fish. The current paper says that warming is causing a decline in fish abundance. Yet an earlier study, of which the UofA scientist was a co-author, says the fish decline is caused by land disturbance. “Watershed deforestation, road building, and other anthropogenic activities result in sediment inundation of lacustrine habitats.” “Our faunal analyses suggest that all three taxonomic groups are negatively affected by sediment inundation but may have varying response thresholds to disturbance.” (Citation: Conservation Biology, vol. 13, no. 5, Oct. 1999).