Monday, August 04, 2008

Pesky British navy logbooks

Britain's great seafaring tradition is to provide a unique insight into modern climate change, thanks to thousands of Royal Navy logbooks that have survived from the 17th century onwards. The logbooks kept by every naval ship, ranging from Nelson's Victory and Cook's Endeavour down to the humblest frigate, are emerging as one of the world's best sources for long-term weather data. The discovery has been made by a group of British academics and Met Office scientists who are seeking new ways to plot historic changes in climate.

"This is a treasure trove," said Dr Sam Willis, a maritime historian and author who is affiliated with Exeter University's Centre for Maritime Historical Studies. "Ships' officers recorded air pressure, wind strength, air and sea temperature and other weather conditions. From those records scientists can build a detailed picture of past weather and climate."

A preliminary study of 6,000 logbooks has produced results that raise questions about climate change theories. One paper, published by Dr Dennis Wheeler, a Sunderland University geographer, in the journal The Holocene, details a surge in the frequency of summer storms over Britain in the 1680s and 1690s. Many scientists believe storms are a consequence of global warming, but these were the coldest decades of the so-called Little Ice Age that hit Europe from about 1600 to 1850.

Wheeler and his colleagues have since won European Union funding to extend this research to 1750. This shows that during the 1730s, Europe underwent a period of rapid warming similar to that recorded recently - and which must have had natural origins. Hints of such changes are already known from British records, but Wheeler has found they affected much of the north Atlantic too, and he has traced some of the underlying weather systems that caused it. His research will be published in the journal Climatic Change.

The ships' logs have also shed light on extreme weather events such as hurricanes. It is commonly believed that hurricanes form in the eastern Atlantic and track westwards, so scientists were shocked in 2005 when Hurricane Vince instead moved northeast to hit southern Spain and Portugal. Many interpreted this as a consequence of climate change; but Wheeler, along with colleagues at the University of Madrid, used old ships' logs to show that this had also happened in 1842, when a hurricane followed the same trajectory into Andalusia.

The potential of Royal Navy ships' logs to offer new insights into historic climate change was spotted by Wheeler after he began researching weather conditions during famous naval battles. Later, as global warming moved up the scientific agenda, he and others realised that the same data could shed light on historic climate change. He said: "British archives contain more than 100,000 Royal Navy logbooks from around 1670 to 1850 alone. They are a stunning resource."

Most of these earlier documents contain verbal descriptions of weather rather than numerical data, because ships lacked the instruments to take numerical readings. However, Wheeler and his colleagues found early Royal Navy officers recorded weather in consistent language. "It means we can deduce numerical values for wind strength and direction, temperature and rainfall," he said. The information will ultimately contribute to the International Comprehensive Ocean-Atmos-phere Data Set, a global database maintained by the National Oceanic and Atmospheric Administration, a US government agency.

Wheeler makes clear he has no doubts about modern human-induced climate change. [He would be out on his ear if he said otherwise] He said: "Global warming is a reality, but what our data shows is that climate science is complex and that it is wrong to take particular events and link them to CO2 emissions. These records will give us a much clearer picture of what is really happening."

The Met Office has also set up a project, part-funded by Defra, the environment ministry, to study 900 logbooks kept by the East India Company on voyages between Europe and the Far East between 1780 and 1840. Its vessels carried thermometers and barometers so the data is of higher quality.

Faced with logs taken over so many voyages, the researchers have had to be selective. One of the most avid recorders of such data was Nelson himself, whose personal logbook records the air pressure and other readings he took up to several times daily.


Law of Averages

By Dr. Mel Goldstein, a Meteorologist on Connecticut's TV News Channel 8

Do you believe that most things in life balance out, even the weather? We have our happy days, unhappy ones, healthy days, less healthy ones, and then of course, our wet and dry spells, our cold and warm ones.

If you enjoy trying your luck whether it be at the casino, or on Wall Street, if you can stay in long enough, cycles have a way of turning life around for you. But at the card table, you do have the option of cashing in; but, at the weather table, you are stuck, that option is not your choice. Now, that we are embroiled in a discussion of global change, one has to wonder where the law of weather averages will hold true here. I'm just finishing a book on Connecticut weather, I'd love your input.

The book has been a year and a half in the writing. A huge task, and I labored over the final chapter which dealt with global change. Sure that has been warming since the mid 1980s, especially, and you can see that clearly when looking at the records, but the question remains whether this is relatively a temporary thing caused by natural cycles, or has man-made influences made the process irreversible.

The International Panel on Climate Change(IPCC) is convinced and has data to show, that natural cycles alone could not account for the degree of warming which has taken place. But many of these people are not frontline weather forecasters, and if there are sceptics in the bunch, these by and large come from this group. We deal with change all the time. We are familiar will the limitation of the computer model equations and inputs. Look at the past weekend-the machines projected a few Sunday showers, and instead, we had a deluge, all day. If these inputs and equations have trouble in the short-term, can we truly trust them to tell us a 20-year or 50-year forecast?

Maybe there will be a law of weather averages even here, and we will return to a colder cycle. But one huge advantage to going green is that we will clear the air pollution level to a much more desirable level. It is about time that we controlled pollutants like hydrocarbons and nitrogen oxides as well smog and ozone - and then there are the political and social aspects of the change. I just hope that if we do go through a colder cycle, green folks don't get cold feet.


Snow greets visiting hikers at Mount Rainier

Cool ocean temperatures in the southern Pacific Ocean -- a phenomenon known as La Nina -- chilled sunny expectations this summer for thousands of visitors to Mount Rainier National Park.

Those who arrived here in July planning to backpack or hike its famous sub-alpine wildflower meadows found snow instead, six feet in places, though sunny daytime temperatures reach into the 70s.

The popular mountain that draws 1.5 million visitors each year received 950 inches of snow last winter, 300 inches more than its 650-inch average. Park officials said a cooler than usual spring also pushed back the thaw.

"A lot of people were disappointed to come and find snowy meadows," said Mike Punches, a park interpreter at the Henry M. Jackson Visitor Center at Paradise, located 5,400 feet above sea level. "Normally the wildflower season is all of July and August. The early bloomers come the first of July.


What are the odds that we're baking the planet?

Eco-campaigners claim that climate catastrophe is a virtual certainty. A little bit of maths and logic suggests otherwise

For some years now, governments, industry, and private citizens have been regularly chastised by environmental activists for not doing more to limit greenhouse gases, the presumed cause of global warming. But lately a far more serious charge has been made. In June, the oft-quoted NASA climate scientist James Hansen appeared before a United States congressional committee. He said that the directors of fossil-fuel companies `should be tried for high crimes against humanity and nature' (1).

But these people shouldn't be prosecuted just for producing fossil fuels. Hansen thinks they should also be prosecuted because, as he wrote in the UK Guardian: `Instead of moving heavily into renewable energies, fossil companies choose to spread doubt about global warming, as tobacco companies discredited the smoking-cancer link.' (2) In other words, fossil fuel company directors should be prosecuted for what they say, as well as for what they do.

It's a common type of argument, familiar to anyone acquainted with totalitarian regimes: the nation (or revolution, race, class, etc) is in grave peril from (fill in the blank). But there are traitors among us who spread lies, seeking to weaken our resolve. They must be restrained (temporarily, of course) for the good of us all.

But there's no reason this policy should only be applied to peddlers of coal and oil. Anyone who casts doubt on the reality of global warming would be equally guilty of imperilling the entire Earth. In the face of the imminent and overwhelming threat of catastrophic climate change, strict measures would (regrettably) have to be taken.

Environmental activists describe anyone who is sceptical of the urgent need to reduce greenhouse gases (GHGs) as a `climate-change denier'. The similarity of this phrase to the pejorative epithet `Holocaust denier' is not accidental. If you deny something, you believe it's false. If you're sceptical about it, you're not convinced it's true. This is an important logical distinction. But it's one that environmental activists are happy to obscure. It's also important to distinguish the varying degrees of climate-change scepticism that exist. For example, someone might be sceptical about one or more of these commonly accepted statements:

Global warming is really happening.

Global warming is caused by man-made greenhouse gases (GHGs).

Global warming will be harmful.

GHG emissions must be reduced in order to combat global warming.

And if there really is an urgent need to reduce GHG emissions, all four of these statements must be true. Predictably, James Hansen has no doubt: `I can assert that these conclusions have a certainty exceeding 99 per cent.' (3)

But just how likely is it that all four of these statements are true? Fortunately, this question is easy to answer. All we need to do is consult the latest report of the Intergovernmental Panel on Climate Change (IPCC), along with an elementary logic textbook.

The IPCC Synthesis Report of 2007 is scrupulous in specifying the probability of the various statements it makes about climate change. For example, consider this sentence on page 30: `Average Northern Hemisphere temperatures during the second half of the twentieth century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1,300 years.' And this one on page 39: `Most of the observed increase in global average temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic GHG concentrations.' The italics are in the original.

Obviously this supports our statements 1 and 2. What the italicised words mean in terms of the percentage likelihood of causation or occurrence is clearly set out on page 27:

95-99 per cent: Extremely likely

90-94 per cent: Very likely

66-89 per cent: Likely

50-65 per cent: More likely than not

33-66 per cent: As likely as not

Below 33 per cent: Unlikely

(The numbers given here for `more likely than not' and `as likely as not' aren't misprints: the ranges overlap in the report itself.)

Now we'll turn to our Logic for Beginners textbook. Suppose the two statements A and B are independent: that is, the truth of A doesn't make B any more or less probable. Then the probability of them both being true is equal to the probability of A multiplied by the probability of B. Consider the classic textbook example of the coin toss. The likelihood of tossing heads or tails when tossing a coin isn't affected by previous tosses: no matter how many heads you've tossed already, the probability that the next will be heads is still fifty-fifty. (Many a gambler has come to grief by ignoring this basic principle.) So the two statements:

A. The first toss is heads.

B. The second toss is heads.

are independent. Since the probability of each statement is 50 per cent, or 0.5, the probability of tossing two heads in a row is 0.5 x 0.5 = 0.25, or 25 per cent.

When the statements aren't independent, the calculation is a bit more complicated. And obviously our statements 2, 3, and 4 aren't independent of 1. But since the IPCC probability estimates take these dependencies into account, the simple multiplication rule of the coin toss example will give the correct result.

As we've seen, the IPCC rates statement 1 as `very likely', so the probability of this statement is in the range 90-94 per cent. The IPCC also rates statement 2 as `very likely'. Using the multiplication rule, we can calculate the probability of statements 1 and 2 being true together as 81-88 per cent. This falls within the range the IPCC describes as `likely'.

So we can see already that James Hansen's claim of `certainty exceeding 99 per cent' goes well beyond the evidence provided by the IPCC report. It seems he's placed himself firmly on the lunatic fringe of environmental activism.

Of course, this doesn't mean that climate-change scepticism is warranted. The probability that statements 1 and 2 are both true is still over 80 per cent, according to the IPCC data. But statements 3 and 4 have to be considered as well. Again, all four must be true if the calls for urgent action on GHGs have any merit.

The IPCC report examines a number of scenarios that make different assumptions about world population and economic growth. For each scenario, it estimates how much average global temperature would rise by the end of the twenty-first century. These estimates range from 0.6 to 4.0 degrees. The IPCC also estimates what effects these different levels of global warming might have on weather, food production, ecological systems, human health, and so on. For the most part, these effects are harmful ones, such as increased drought, heatwaves, floods, and more intense storms.

But some benefits are also mentioned. Under some of the scenarios, longer growing seasons and increased precipitation result in an overall increase in global food production. Warmer winters also have some health benefits, and significantly reduce energy consumption.

However, the IPCC report makes no predictions about how much future global warming will occur, since it doesn't assign probabilities to any of these scenarios. Although some amount of warming is predicted in all of the scenarios, the report reveals much uncertainty about how harmful the effects might be. Nevertheless, let's do our best for the case against GHGs, and assign statement 3 to the IPCC's `likely' category. This gives it a probability range of 66-89 per cent.

Using the multiplication rule once again, we find that the probability of statements 1, 2, and 3 all being true is 53-79 per cent. This falls mainly within the range the IPCC describes as `more likely than not'.

Finally we come to statement 4. Given statement 2, it may seem obvious that reducing man-made GHGs would reduce global warming. But unfortunately, the physical world is more complicated than that. The fact that X is the cause of Y doesn't guarantee that doing something to X will have any effect on Y. To choose a simple example, you can't fix a broken window by getting rid of the rock that broke it. And many environmentalists - including James Hansen - talk ominously about `tipping points', beyond which further global warming would be unavoidable whatever we did.

So there's no guarantee that reducing man-made GHGs would have any effect on global warming. Still, let's assume our statement 4 is also `likely' to be true. Using the multiplication rule one last time, it turns out the probability of statements 1 through 4 all being true together is 35-70 per cent. This falls almost entirely within the range the IPCC calls `as likely as not'.

It's easy to predict the environmentalist response: `We should err on the side of caution, and try to cut GHG emissions anyway.' This would be perfectly reasonable if limiting GHGs would itself have no adverse consequences. But implementing policies like those set out in the Kyoto Protocol would have significant economic costs.

More strident environmentalists would no doubt like to tip this balance by replacing our statement 3 with something like: `Global warming will be catastrophic.' But there's nothing in the IPCC report that justifies such a claim. This puts it in the same league with statements like: `Man-made GHGs have saved us from another ice age.' Based on the IPCC report, both statements are equally likely.

People are notoriously error-prone when reasoning about probability. When told that two statements are each very likely to be true, most people immediately conclude that the two taken together are just as probable. But this isn't so. Claiming that two things are true just gives you twice as many opportunities to be wrong. Uncertainties multiply, however slight each individual one might be.

Science can't always give us definite answers to our questions, even when the issues involved are very important to us. But it often can tell us how certain we should allow ourselves to be. And the certainty expressed by far too many environmentalists goes well beyond what the science will support.


South African nonsense refuted

Comment on "Global warming hits Midmar Dam" (on this blog July 23) by Umgeni Water

The article reaches the opposite conclusion to what is in the published paper "Toxic blooms in Midmar Dam". This constitutes an incorrect interpretation of the paper. CSIR researcher Dr Paul Oberholster and colleague Dr Anna-Marie Botha actually conclude that the winter bloom of Microcystis spp. during 2005 occurred with a low average surface water temperature of 10,1øC and that this is "totally antithetical" to the norm. In other words, it is not temperature that seemed to be the cause of the algae bloom but "that nitrogen plays a large role in the changes to the phytoplankton community composition". There is even reference in the publication to the fact that the sampled sites of the study "are part of the Midmar game park sanctuary, and waterfowl may be a contributory factor to the high nutrient values in the winter months".

Midmar Dam, like other Umgeni Water (UW) dam water resources, is comprehensively monitored by UW for a wide variety of analyses, including algae down to genus level. Sampling is done near the wall and is representative of the main body of water where water is abstracted for treatment. This enables Umgeni Water to identify and react to potential problems so that treated water is always safe to drink.

There is currently no major change being seen in the behaviour of the water temperature in the Midmar impoundment. On the contrary, median annual temperatures have cooled slightly in recent years. Winter minimum temperatures have behaved similarly. While climate change is a concern and is receiving attention at Umgeni Water, it is the possibility of droughts and floods that are by far the most important problems needing attention.

The article refers to "algae flowers". An algal "bloom" is not an algal "flower" (most are unicellular and cannot flower). A bloom is the name given to a proliferation of algae in very high numbers, usually due to a plentiful supply of nutrients. Without these nutrients, excessive growth is not possible, regardless of temperature. Temperature can have an effect on algal blooms, but different algae have different temperature needs and some algae can develop blooms at low temperatures.

Toxin-producing algae have been detected in Midmar (mostly in summer), but these algae can be found almost everywhere. Midmar has not yet experienced an algal bloom where potential toxin-producing algal numbers have developed to the point where abstracted water quality problems are likely, at any time of the year. The WHO suggests a limit of 100 000 cyanobacterial cells/mL alert level in the water resource, at which cyanotoxins could be present up to 20ug/L.

The average cyanobacterial counts are less than 20 000 cells/ml for the period 1994 to 2008.

In Midmar, small blooms of other algal types that cause related problems have been encountered, but have been minor in nature (causing slight filter blocking). A number of the minor algal blooms that have occurred in Midmar since Umgeni Water monitoring began in the late eighties have occurred in late winter, so this appears to be normal behaviour for this impoundment. These blooms have mostly been of algae called diatoms which do not produce any toxic substances.

All relevant water resource managers involved at Midmar Dam (including the Department of Water Affairs and Forestry and Umgeni Water) are fully aware of the potential problems algae can cause. If a problem is seen to be developing, a wide range of actions can then be taken.

Besides trying to prevent nutrient enrichment in the first place, spilling the dam can remove the problem, provided that there is enough water, and in dams like Midmar there are a number of abstraction depths that can be strategically selected to avoid sucking in algae. Pre-treatment of the raw water can be undertaken to remove the algae, and even more careful than normal treatment processes followed.

At other dams, such as Inanda, where far more nutrients are present and there have been significant and potentially problematic algal blooms in the past, detailed monitoring (including analysis of the algal toxins) has been undertaken. While toxins have been detected in low amounts in some samples, the work has shown that the raw water sent to treatment plants has been entirely safe, even when specifically problematic algae (mostly cyanobacteria, also called blue-green algae) have been present in large numbers. Additionally, Umgeni Water's treatment plants, which are designed to be effective in removing algae, can be and are operated with additional and even more comprehensive treatment to ensure removal of these problems (such as the use of activated carbon). Were a problem algal bloom to affect Midmar, similar additional monitoring and treatment would be undertaken.

Problem algae (both in terms of numbers and particularly the presence of cyanobacteria of concern) are far more likely to result from nutrient enrichment in a dam than from temperature changes. These problems are more likely in summer, but would be of concern no matter what time of year they might occur. The sources of these nutrients are related to the land-use pattern around the water resource.


Garbage correctness in SF

Garbage collectors would inspect San Francisco residents' trash to make sure pizza crusts aren't mixed in with chip bags or wine bottles under a proposal by Mayor Gavin Newsom. And if residents or businesses don't separate the coffee grounds from the newspapers, they would face fines of up to $1,000 and eventually could have their garbage service stopped.

The plan to require proper sorting of refuse would be the nation's first mandatory recycling and composting law. It would direct garbage collectors to inspect the trash to make sure it is put into the right blue, black or green bin, according to a draft of the legislation prepared by the city's Department of the Environment.

The program is designed to limit the amount of food and foliage that goes into the city-contracted landfill in Alameda County, where the refuse takes up costly space and decomposes to form methane, one of the most potent of greenhouse gases. It will also help San Francisco, which city officials say currently diverts 70 percent of its waste from landfills, achieve a goal set by the Board of Supervisors to divert 75 percent by 2010 and have zero waste by 2020.

"If we're truly going to be the city we promote ourselves to be, a world-class, 21st century city that advances its values and principles, we're going to have to try new things," Newsom said Thursday. "People are used to doing things a certain way. And when you change that, they say it can't be done. Well, we've proved them wrong." He pointed to a doubling in the city's recycling rate from 1996 to 2008, but acknowledged "it will take some time" to win over hearts and minds. "People don't knowingly want to waste," Environment Department Director Jared Blumenfeld said. "At the moment, we have a missed opportunity, which is that we're at a 70 percent recycling rate. Overnight we could be at 92 percent if everything people are throwing away that could be reused or recycled actually was."

Plenty of other cities, from Pittsburgh to San Diego, have mandatory recycling. None, however, requires all food waste be composted. Seattle passed a law in 2003 requiring people to have a compost bin but it did not mandate that all food waste go in there. "If they want to throw away food, that's their right," said Brett Stav, a planning and development specialist at Seattle Public Utilities. "We're not banning food from the garbage."

Skeptics call Newsom's plan unworkable and see it as the latest intrusion from heavy-handed city government, which has outlawed smoking in parks and feeding pigeons in much of the city. Duboce Triangle resident Mark Cromwell, a 53-year-old personal assistant, called the proposed law "laughable." "Do we want our garbage collectors to be the meter maids of trash?" Cromwell said. "Good luck placing blame on the recycling criminal, especially in big apartment buildings. I will stop recycling if this law goes into effect just to become an eventual test case. Dictators are anathema, no matter which side of the political spectrum they come from."

The company with the city's garbage and recycling contract also is hesitant to take on enforcement, saying it could slow down service and require extra data entry and information tracking. "We support the goals of the proposed ordinance but believe it needs refinements to be workable for everyone involved, especially the customers," said Robert Reed, a spokesman for Norcal Waste Systems. Norcal is the parent company of San Francisco collectors Sunset Scavenger Co. and Golden Gate Disposal and Recycling Co.

"We are concerned about draft provisions that envision our drivers policing the contents of refuse containers and possibly withholding service if violations were found," Reed said. "A significant increase in time required to service each customer location would mean we would need to have more routes, which means more drivers, trucks, fuel and related resources."

The proposal, which city officials said the mayor could bring to the Board of Supervisors in about a month, calls for every residence and business in the city to have three separate color-coded bins for waste: blue for recycling, green for compost and black for trash. Food vendors would have to supply them for customers. Managers of multifamily or commercial properties would be required to provide them for tenants or employees. Trash collectors would be required to check the bins for proper sorting, which Blumenfeld said would require only a cursory visual inspection, not combing through the contents.

If they found a bin with the wrong material in it, collectors would leave a tag on the container identifying the problem. A second time would result in another tag and a written notice to the service subscriber. On a third offense, the collector could refuse to empty the container, although this would not apply to multifamily properties like apartment buildings or to commercial properties with multiple tenants and joint collection. The city could also levy a fine of up to $500 for the first violation, $750 for the second in one year and $1,000 for the third in a year.

Apartment landlords are concerned that they'll have to pay for a tenant's behavior and won't be able to pass the fine along, said Sean Pritchard, the government affairs director for the San Francisco Apartment Association. "How do you determine which tenant is at fault?" Pritchard said. "Or do we indiscriminately start fining all tenants for one tenant's poor choice of judgment?" Blumenfeld called that fear unnecessary, saying, "We won't enforce against owners of apartment buildings if their tenants don't do this."



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