Climate Change May Alter Natural Climate Cycles of Pacific

ScienceDaily (Oct. 18, 2010) — While it's still hotly debated among scientists whether climate change causes a shift from the traditional form of El Nino to one known as El Nino Modoki, scientists now say that El Nino Modoki affects long-term changes in currents in the North Pacific Ocean.

Photo: en.wikipedia.org

The research is published online in the journal Nature Geoscience.

El Nino is a periodic warming in the eastern tropical Pacific that occurs along the coast of South America. Recently, scientists have noticed that El Nino warming is stronger in the Central Pacific rather than the Eastern Pacific, a phenomenon known as El Nino Modoki (Modoki is a Japanese term for "similar, but different").

Last year, the journal Nature published a paper that found climate change is behind this shift from El Nino to El Nino Modoki. While the findings of that paper are still being debated, this latest paper in Nature Geoscience presents evidence that El Nino Modoki drives a climate pattern known as the North Pacific Gyre Oscillation (NPGO).

"We've found that El Nino Modoki is responsible for changes in the NPGO,"said Emanuele Di Lorenzo, associate professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. "The reason this is important is because the NPGO has significant effects on fish stocks and ocean nutrient distributions in the Pacific, especially along the west coast of the United States."

The NPGO, first named two years ago by Di Lorenzo and colleagues in a paper in Geophysical Research Letters, explained for the first time long-term changes in ocean circulation of the North Pacific, which scientists now link to an increasing number of dramatic transitions in coastal marine ecosystems.

"The ecosystems of the Pacific may very well become more sensitive to the NPGO in the future," said Di Lorenzo. "Our data show that this NPGO is definitively linked to El Nino Modoki, so as Modoki becomes more frequent in the central tropical Pacific, the NPGO will also intensify."

See more: http://www.sciencedaily.com/releases/2010/10/101017133641.htm

What's the carbon footprint of ... building a house

New homes require far less energy to run than older properties, but building them generates plenty of CO2

• More carbon footprints: the internet, cycling a mile, others
• Understand more about carbon footprints

 

New houses such as these ones in south Derbyshire take lots of energy and resources to produce. Photograph: Rui Vieira/PA

 

The carbon footprint of a house:
80 tonnes CO2e: A newbuild two-bed cottage

The carbon footprint of building a house depends on all kinds of things – including, of course, the size of the house and the types of materials chosen.

The estimate of 80 tonnes given above is for the construction of a brand-new cottage with two bedrooms upstairs and two reception rooms and a kitchen downstairs. It's based on a study that I was involved in for Historic Scotland.
The study looked at the climate change implications of various options for a traditional cottage in Dumfries: leave it as it is, refurbish, or knock it down and build a new one to various different building codes. We looked at the climate change impact over a 100-year period, taking into account the embodied emissions in the construction and maintenance as well as the energy used and generated by those living in the building.

Unsurprisingly, the worst option by far was to do nothing and leave the old house leaking energy like a sieve. Knocking down and starting again worked out at about 80 tonnes CO2e whether the house was built to 2008 Scottish building regulations or to the much more stringent and expensive Code for Sustainable Homes Level 5 that demanded 'carbon neutrality'.

Here's how that total broke down for the carbon-neutral option:

• Walls 60%
• Timber 14%
• Pipework and drainage 9%
• Floors 5%
• Slate roof 5%
• Photovoltaic panels 3%
• Other 4%

Eighty tonnes is a lot – equivalent to five brand-new family cars, about six years of living for the average Brit or 24 economy-class trips to Hong Kong from London. But a house may last for a century or more, so the annual carbon cost is much less – and for all the new-build options, the up-front emissions from construction work were paid back by savings from better energy efficiency in 15–20 years.

However, the winning option was to refurbish the old house, because the carbon investment of doing this was just eight tonnes CO2e, and even the highest-specification newbuild could not catch up this advantage over the 100-year period. Once cost was taken into account, refurbishment became dramatically the most practical and attractive option, too.

If this one study is representative, the message for the construction industry is clear. Investment in the very highest levels of energy-efficiency for new homes is, even at its best, an extremely costly way of saving carbon. Investing in improvements to existing homes is dramatically more cost-effective.

See more carbon footprints.

• This article draws on text from How Bad Are Bananas? The Carbon Footprint of Everything by Mike Berners-Lee

www.guardian.co.uk

Pollution is not the reason of temperature drop in Northern Hemisphere around 1970

The new research, led by Dave Thompson from Colorado State University in Fort Collins, US, shows that the top layers of Northern Hemisphere water cooled by about 0.3C between 1968 and 1972, while the South Hemisphere saw approximately the same degree of warming.

But the timescale of the drop is much shorter, than that previously linked to the increasing sulphate aerosols from fossil fuel in the troposphere, or changes in the climate of the world’s oceans that evolve over decades (oscillatory multidecadal variability).

Photo: ijolumoet.com

This research suggests that the explanation of the cooling could lie somewhere else, it is not clear where, since the effect of aerosols is expected to be more gradually.

A model developed by Thompson which uses data collected by ships and buoys over the past two and a half centuries examined temperature change on a month-by-month basis, unlike previous studies that look at temperature change on a decadal scale.

The team fed the data into a model that blocks out short-term changes in ocean temperature – triggered, for example, by volcanic eruptions which spew sulphur aerosols into the atmosphere. This allowed them to identify changes in ocean temperature that weren't linked to natural variation; The Guardian wrote on 22 September 2010.

It is unclear what caused the cooling process, but an unusually large discharge of ice from the Arctic Ocean in 1967 is the reason of a 10,000 cubic kilometre pool of fresh water from the coast of Greenland, which appears to have lowered the salinity of water in the North Atlantic, according to Mark Maslin of the Environment Institute at University College London.

One possibility is the Great Salinity Anomaly (GSA) which presumably interrupted the mixing process of cooled surface water and warm deep water that caused a cool period by dumping light, fresh water on the surface.

Still, it is a fact that currently greenhouse gases are warming up the Planet.


Written by Jasmina Nikoloska
Sources: Abstract of the paper in Journal Nature

               The Guardian