Sunday, 29 July 2012

Climate stuff from the week 23-29/7/12

[video] Potholer54: 'Medieval Warm Period -- fact vs. fiction'

'Rise in temperatures and CO2 follow each other closely in climate change'

An analysis of ice cores, from various locations across Antarctica, and contain tiny bubbles - samples of ancient air - have provided evidence that past temperature fluctuations are succeeded by CO2 release/absorption not in the thousands of years after, but in a few centuries.
Milankowitch cycles are variations in the Earth's orbit around the Sun, the Earth's tilt and the orientation of the Earth's axis, and are responsible for tens of thousands year long cycles, so cause the Earth's climate to shift between long ice ages of approximately 100,000 years and warm interglacial periods, typically 10,000 – 15,000 years.
These periods are far too long to explain the well-above-baseline fluctuations observed in the last century and a half; solar cycles (fluctuations in the Sun's output) have a period of 11 years, and so are too short to explain the last century and a half's trend.
"What we are observing in the present day is the mankind has caused the CO2 content in the atmosphere to rise as much in just 150 years as it rose over 8,000 years during the transition from the last ice age to the current interglacial period"

'Fools' gold found to regulate oxygen'
"Pyrite is an iron-sulfur mineral (also known as fools' gold), which forms when microbes in seafloor sediments use the sulfur dissolved in seawater to digest organic matter. The microbes take up sulfur in the form of sulfate (bound to four oxygen atoms) and release it as sulfide (with no oxygen). Oxygen is released during this process, thus making it a source of oxygen in the air. But because this part of the sulfur cycle was thought be minor in comparison to sulfate evaporite burial, (which does not release oxygen) its effect on oxygen levels was also thought to be unimportant."

"the production and burial of pyrite has been much more significant than previously thought, accounting for more than 80% of all sulfur removed from the ocean (rather than the 30-40% in prior estimates). As opposed to the variability they saw for sulfate evaporite burial, pyrite burial has been relatively stable throughout the period. The analysis also revealed that most of the sulfur entering the ocean washed in from the weathering of pyrite exposed on land. In other words, there is a balance between pyrite formation and burial, which releases oxygen, and the weathering of pyrite on land, which consumes it. The implication of these findings is that the sulfur cycle regulates the atmospheric concentration of oxygen more strongly than previously appreciated."

Surface water on Greenland has, this summer, thawed out in areas never-before-seen in 30 years of satellite monitoring. The last record of it happening dates to 1889.
"Measurements from three satellites showed that on July 8, about 40 percent of the ice sheet had undergone thawing at or near the surface. In just a few days, the melting had dramatically accelerated and an estimated 97 percent of the ice sheet surface had thawed by July 12"
"On average in the summer, about half of the surface of Greenland's ice sheet naturally melts. At high elevations, most of that melt water quickly refreezes in place. Near the coast, some of the melt water is retained by the ice sheet and the rest is lost to the ocean. But this year the extent of ice melting at or near the surface jumped dramatically."
Hopefully, this year's data will provide an anomalously high peak -- area is not equal to volume, though, so we should not infer volume of meltwater from thawed area -- other data suggests that most melting will happen around the edges of the ice sheet.
"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time"
As industry-driven climatic change continues, we should expect them to become more frequent, but *how* frequent is what will make the difference to people and other animals living in Greenland.

'US 'extreme drought' zones triple in size'
"Things have really developed over the last two months and conditions have worsened just that quick and that is really unprecedented"
Because of this: "President Barack Obama's administration has opened up protected US land to help farmers and ranchers hit by the drought and encouraged crop insurance companies to forgo charging interest for a month."
"Officials have said the drought will drive up food prices since 78 percent of US corn and 11 percent of soybean crops have been hit and the United States is the world's biggest producer of those crops."
Climatology predicts that droughts such as these will increase in frequency and intensity, as the atmosphere warms and dries.

'Seven countries join anti-soot and methane campaign'
"A coalition of countries and agencies seeking to curb Earth-warming pollutants like soot released by wood-fired ovens and methane from oil extraction, on Tuesday welcomed seven new members to its fold."
"At a meeting in Paris, the Clean Air and Climate Coalition, launched by US Secretary of State Hillary Clinton in February, said Britain, Denmark, Finland, France, Germany, Italy and Jordan were its latest members. They joined the United States, Bangladesh, Canada, Colombia, the European Commission, Ghana, Japan, Mexico, Nigeria, Norway, Sweden, the World Bank, the UN Environment Programme (UNEP) and the Stockholm Environment Institute -- bringing to 21 the number of members of the voluntary coalition."
"Short-lived pollutants like black carbon or soot, methane and fluorinated gases called HFCs can potentially be eliminated from the atmosphere in a much shorter period of time than CO2, which is the main target of international efforts to curb global warming"
"It is a matter of public health. Over two million people in the world, perhaps even four million according to the latest estimates from scientists, are dying every year from outdoor air pollution... Another two million die annually from indoor pollution from cooking stoves."

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