Tag Archives: global-warming

Climate change all over the place

And speaking of climate change there is an interesting story at the BBC about how monsoons/droughts, as recorded in the concentrations of minerals in stalactites, have been linked with Chinese dynasties:

By comparing the rain record with Chinese historical records, Pingzhong Zhang of Lanzhou University in China, and colleagues, found three out of five “multi-century” dynasties – the Tang, the Yuan and the Ming – ended after several decades of weaker summer monsoons with drier conditions.

These moisture-laden winds bring rain necessary for cultivating rice. But when the monsoon is weak, the rains stall farther south and east, depriving northern and western parts of China of summer rains.

This could have led to poor rice harvests and civil unrest, the researchers speculate.

It’s an interesting theory, and reflects how important climate is in the lives of humanity, and also in the lives of lemmings, with the discovery that the lemming population of Norway is no longer as fecund as it once was:

The research team, composed of Norwegian and French scientists, believes the winters are now too humid, leading to the “wrong kind of snow“.

This results in a less stable subnivean space (the space between the ground and the snow layer above), meaning substantially fewer animals survive until spring.

Aww. But apparently it’s not all bad news vis a vis climate change. Apparently certain Alaskan glaciers have in fact grown this year for the first time in 200 years.

This will please Sarah Palin – who apparently has only recently discovered that Africa is a continent, not a country.

Congrats on the win, America!

As to the glaciers – only time will tell.

[wanxiang cave image from BBC News, lemming from kdleditsch on flickr]

U.S. Presidential science

politicsI try to keep partisan stuff out of these posts, but somebody needs to note that Obama has responded at some length to 14 questions on science policy issues posed to him by Sciencedebate 2008, representing a truckload of scientific associations. McCain hasn’t answered yet. NPR has a short item about both candidates’ health policies. And the AAAS just put out a “policy alert” on a few of Gov. Palin’s views on evolution, global warming, and other topics. Not always sexy issues to the media, but something for American voters to think about.

[Story tips: slashdot, Framing Science; Political Studies by minkymonkeymoo]

Global warming and the Plague (yeah, that Plague)

plague-towerOutbreaks of bubonic plague in the U.S. might be linked to climate change in the Pacific Ocean.

Scientists from Norway, The US and Sweden found that the number of infections in the US seemed to shift along with changing climate conditions known as the Pacific Decadal Oscillation (PDO).

The outbreaks seemed to occur during times of warm, wet conditions, authors wrote in the Royal Society journal Biology Letters.

Global warming might mean fewer cases in a hotter, drier North America, but parts of the world expected to see warmer, moister tempertures might not be so lucky.

[Plague tower, Austria by celesteh]

Hydrogen Dreams

One of my bugbears is the constant implication in the popular press that the twin problems of anthropogenic global warming and peak oil will be solved by the mythical “hydrogen economy.”

Take this article in The Guardian newspaper:

The main fuels used in history form a nearly exact sequence, from ones having hydrogen_carless hydrogen to ones having more. Wood and charcoal were the earliest fuels, and have only a little hydrogen. Much of their burning is wasted in pouring out great gusts of carbon, which was needed to build up the tree from which the wood came, but doesn’t do much for the user burning that wood.

Coal has more hydrogen, and its burning can be cleaner. Oil – which dominated next – has yet more hydrogen per unit of carbon; natural gas has even more, and its burning is the cleanest and most efficient of them all. The trend line points pretty strongly to a pure hydrogen economy – but when that will occur is in the hands not of the scientists, but our wise political masters.

Hydrogen fuel cells have some promise as an energy storage medium, but you still need a source of energy in the first place: much of the commercial hydrogen produced today is actually produced from natural gas in a process which still produces carbon dioxide emissions.

Alternative methods using biological extraction have proven successful – but they still don’t tackle the nuclearfundamental problem of where the energy to extract the hydrogen comes from. With oil running out and our current industrial infrastructure reliant on dumping stored carbon dioxide into the atmosphere this is the problem that needs to be solved.

And if the basic problem is getting energy, wouldn’t it be better to concentrate on that and, once this problem is solved, use this source of hydrogen-producing energy to produce petroleum via the Fischer-Tropsch process and save £X trillions by avoiding upgrading our entire transport infrastructure to use hydrogen tanks and fuel cells?

My conclusion: every penny of research currently being poured into the hydrogen economy should be diverted into developing cleaner nuclear fission and synthetic petroleum fuel combined with hybrid electric-petrol vehicles.

Monday rant over.

[main article from The Guardian][other articles from PhysOrg][images from felixmolter and gavindjharper]

Study finds little solar link to cloud formation, not the driver of climate change?

A pretty picture fo the sun, which doesn\'t look like it\'s causing global warmingTwo of the major criticisms of global warming theory I’ve seen recently have been that a) 1998 was actually the hottest year on record and since then it’s been cooler and b) that solar winds and cosmic rays are driving the climate change process, not human emissions.

These are valid points and scientists have been spending a lot of time researching their impact. Lancaster University have just released a major report on the latter, concluding from 20 years of data that global temperatures have little influence from solar activity. The original hypothesis, by Danish scientist Henrik Svensmark, hypothesized that when the 11 year cycle of solar wind is weak, more cosmic rays make it through the earth’s atmosphere, making more clouds and cooling the earth. Correspondingly, when solar wind is strong, Svensmark’s theory expected more global warming. However, with solar winds currently near their minimum, global temperatures are still high. The Lancaster study used three different experimental methods to find little correlation between the two, contradicting Svensmark’s theory, which was heavily cited in the documentary ‘The Great Global Warming Swindle’.

Related to this discussion is the citing of 1998, the hottest year on record, as proof that global temperatures are going down. This is a compelling argument on the surface but when you look at other global weather patterns the reason for the difference in numbers becomes apparent. 1998 was incredibly hot in main part because it was in an El Nino cycle, in which the warming of the Pacific Ocean disrupts weather patterns. Today however, we are in the midst of a significantly strong La Nina event, the sister condition that dampens global temperatures. This means that whilst it will still likely be in the top ten hottest years, 2008 will not be a very hot year, due to that effect.

Both the cosmic ray and 1998 hypotheses were picked up as proof that global warming doesn’t exist. These criticisms are important because by either disproving or proving them to be right, our understanding of this science improves. When the outlying criticisms of climate change are themselves shown to be lacking, the consensus grows stronger and vice versa. Like all cutting edge science, it’s a learning process.

UPDATE: you can read the Lancaster paper here, whilst some of Svensmark’s papers are available on his website, although I can’t find any after 2001.

[via BBC Science, picture by Feuillu]