A group of Swedish scientists at the University of Gothenburg have published a paper in which they argue that spreading peatlands are inexorably driving planet Earth into its next ice age, and the only thing holding back catastrophe is humanity's hotly debated atmospheric carbon emissions.
"We are probably entering a new ice age right now. However, we're not noticing it due to the effects of carbon dioxide," says Professor of Physical Geography Lars Franzén, from the Department of Earth Sciences at Gothenburg uni.
Franzén and his colleagues have examined various scenarios for the peatlands of Sweden, which are a continually expanding "dynamic landscape element". According to the scientists:
Peatlands grow in height and spread across their surroundings by waterlogging woodlands. They are also one of the biggest terrestrial sinks of atmospheric carbon dioxide. Each year, around 20 grams of carbon are absorbed by every square metre of peatland.
The scientists have calculated that the potential is there for Swedish peatlands to triple in extent, enormously increasing their carbon sink effect. By extrapolating to include the rest of the world's high-latitude temperate areas - the parts of the globe where peatland can expand as it does in Sweden - they project the creation of an extremely powerful carbon sink. They theorise that this is the mechanism which tends to force the Earth back into prolonged ice ages after each relatively brief "interglacial" warm period.
"Carbon sequestration in peatland may be one of the main reasons why ice age conditions have occurred time after time," says Franzén.
With no other factors in play, the time is about right for the present interglacial to end and the next ice age to come on. Indeed, Franzén and his crew think it has barely been staved off by human activity:
The researchers believe that the Little Ice Age of the 16th to 18th centuries may have been halted as a result of human activity. Increased felling of woodlands and growing areas of agricultural land, combined with the early stages of industrialisation, resulted in increased emissions of carbon dioxide which probably slowed down, or even reversed, the cooling trend.
Other scientists
have attributed the Little Ice Age to a quiet period in the Sun's activity: others say it was purely a local effect in Europe, though that theory has
lately been disproved by research in Antarctica.
In any case, the scientists assess that if it weren't for human activity such as carbon emissions, we could expect a new ice era in short order. They write:
Thus, on a global scale, carbon sequestration in peatlands may have had important climate cooling effects towards the ends of previous interglacials ... It cannot be ruled out that similar effects would be seen in a hypothetical Holocene lacking human presence.
It's probably worth noting that the great physicist Freeman Dyson long ago suggested that only relatively small amounts of new peatland would be enough to sequestrate colossal amounts of CO
2 from the air. Other scientists
have noted in recent times that brief warming spells like that observed at the end of the 20th century appear to have occurred towards the end of previous interglacial periods - just before the glaciers returned.
If Franzén and his team are right, the big chill is now under way, and is only just being held off by increasing human carbon emissions - perhaps explaining why temperatures have been merely flat for the last 15 years or so, rather than descending.
The Swedish scientists' paper is published in the peer-reviewed journal
Mires and Peat, and can be read
here in pdf.
Comment
Naturally this theory runs counter to the global warming scenario as presented by many other scientists and most of the media. That stance has lately been boosted by wildly unjustifiable assertions that global warming caused Hurricane Sandy. Unfortunately if you believe that isolated events prove theories, you would pretty much have to accept that global warming has stopped: ten to fifteen years of flat temperatures, or even a few very cold winters - both of which have just happened - are a lot more significant than one storm (and they still aren't significant enough to mean anything much in a climate context).
WARNING FROM RAEL: For those who don't use their intelligence at its full capacity, the label "selected by RAEL" on some articles does not mean that I agree with their content or support it. "Selected by RAEL" means that I believe it is important for the people of this planet to know about what people think or do, even when what they think or do is completely stupid and against our philosophy. When I selected articles in the past about stupid Christian fundamentalists in America praying for rain, I am sure no Rael-Science reader was stupid enough to believe that I was supporting praying to change the weather. So, when I select articles which are in favor of drugs, anti-semitic, anti-Jewish, racist, revisionist, or inciting hatred against any group or religion, or any other stupid article, it does not mean that I support them. It just means that it is important for all human beings to know about them. Common sense, which is usually very good among our readers, is good enough to understand that. When, like in the recent articles on drug decriminalization, it is necessary to make it clearer, I add a comment, which in this case was very clear: I support decriminalizing all drugs, as it is stupid to throw depressed and sad people (as only depressed and sad people use drugs) in prison and ruin their life with a criminal record. That does not mean that there is any change to the Message which says clearly that we must not use any drug except for medical purposes. The same applies to the freedom of expression which must be absolute. That does not mean again of course that I agree with anti-Jews, antisemites, racists of any kind or anti-Raelians. But by knowing your enemies or the enemies of your values, you are better equipped to fight them. With love and respect of course, and with the wonderful sentence of the French philosopher Voltaire in mind: "I disapprove of what you say, but I will defend to the death your right to say it".~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0 ความคิดเห็น:
แสดงความคิดเห็น