Here's a quick write up of several news stories of interest to those tracking global climate change - which should be all of us at this point in time! The BBC is one source. Daily they do great coverage of science news. New Scientist is another place to get a good overview of the latest developments.
Today's run down looks at the connection between Ireland and Greenland, and adds the Mystery of the Plants. More below the Orange Omnilepticon.
While Europe was spending the Dark Ages by pretty much letting frills of civilization like record keeping slide, Ireland in its splendid isolation managed to support a number of religious communities. They kept careful records of notable events, as this BBC story reports.
In the dim light of the Dark Ages, the Irish literary tradition stands out like a beacon.
At monastic centres across the island, scribes recorded significant events such as feast days, obituaries and descriptions of extreme cold and heat.
These chronicles are generally known as the Irish Annals and in this report, scientists and historians have looked at 40,000 entries in the texts dating from AD431 to 1649.
The researchers also looked at the Greenland Ice Sheet Project (GISP2) ice-core data.
When volcanoes erupt, they produce sulphate aerosol particles which down the centuries have been deposited on and frozen in ice sheets, leaving an extremely accurate temporal record of the event.
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The scientists in the team identified 48 volcanic eruptions in the time period spanning 1,219 years. Of these, 38 were associated closely in time with extreme weather events identified in the Irish texts.
"These eruptions occur and they override existing climate patterns for a period of two or three years," said Dr Ludlow.
"And it is clear from the sources that they cause a lot of devastation among societies at the time - whether it was the mass mortality of domestic animals or humans, or indirectly by causing harvest failure."
Think of these events as natural mini-experiments in climate change. A single volcanic eruption can put enough material into the atmosphere to disrupt normal climate patterns for several years. In Ireland this resulted in colder winters, with all the other consequences of such. While this doesn't give us a direct handle on what man-made activities are doing to climate globally, it does indicate how sensitive weather patterns can be.
It also gives support to geoengineering proposals that suggest one way to deal with rising global temperatures is to mimic the action of volcanoes by injecting material into the upper atmosphere to block and/or reflect sunlight. It shows it might work in principle.
But...there are several problems that remain. It's difficult to predict ahead of time exactly how climate patterns would be affected around the world, it's not the kind of thing that can be easily reversed if it turns out to be wrong, and creating volcanic eruptions or their equivalent on demand is a daunting idea. (The BBC has a related article on the 4 ways volcanoes kill. They don't sound like a great deal of fun.)
Drastic as that may sound, we're already engaged in unintentional geoengineering as it is. The rise of carbon dioxide to unprecedented levels from human activity is already having effects around the world. It would seem to reasonable to try to reverse that trend before we have no choice but to resort to more drastic measures.
Meanwhile, what's up with plants? New Scientist offers up reports that the earth may be seeing a rise in plant growth in some regions because of increasing CO2 in the air. The article takes a somewhat hopeful tone:
The extra plant growth could have knock-on effects on climate, Donohue says, by increasing rainfall, affecting river flows and changing the likelihood of wildfires. It will also absorb more CO2 from the air, potentially damping down global warming but also limiting the CO2 fertilisation effect itself.
Donohue cannot yet say to what extent CO2 fertilisation will affect vegetation in the coming decades. But if it proves to be significant, the future may be much greener and more benevolent than many climate modellers predict.
There have been those pooh-poohing the hazards of rising CO2 by saying it simply means our crops will grow better. As the article notes, a large enough increase in plant growth would in effect soak up the extra CO2, putting an upper limit on the increase.
There are problems with that optimistic interpretation however. For one, CO2 levels still seem to be increasing faster than plant growth. There's no way to know how long an increase in plant growth would continue as climate change progresses, OR whether that plant growth would somehow slow or reverse it. Exactly where and how this extra growth is manifesting is still uncertain. It's also more than a race between plants and CO2; other trends like melting of the permafrost, loss of ice cover, shifts in ocean currents are just a few of the other things happening that have to be taken into account.
There are a few things we can be certain of at this point though. Human activity is reshaping the world. CO2 levels are now higher than they've been in recorded human history. Climate patterns are changing around the world in ways that are not good. There will be increasingly severe consequences (sea level rise, mass extinctions, famine, disease, etc.) as this continues. We have probably already reached a point where there are unavoidable changes coming, even if we act now to cut greenhouse gas emissions back to sustainable levels.
And there is one fact no one can deny. Every second that goes by is one less second we have to start turning things around.
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