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Impacts of glacier mass loss

Snippets, Environment
Last Updated 20 September 2017, 11:15 IST

RAPID SHRINKAGE

Researchers have warned of an urgent worldwide need to address a broad spectrum of cascading impacts of glacier mass loss on downstream systems. In their paper, published in Proceedings of the National Academy of Sciences, the authors synthesised currently available evidence and documented the profound impact on freshwater and near-shore marine systems.

Glaciers cover close to 10% of the Earth’s land surface but are shrinking rapidly across most parts of the world. Glacier shrinkage will alter sediment transport, and biogeochemical and contaminant fluxes from rivers to oceans. An unexpected impact of glacier shrinkage is the liberation of contaminants including emission products from industrial activity such as black carbon and associated compounds, mercury, pesticides, and other persistent organic pollutants.

Though there is uncertainty in the release of these legacy contaminants from glacierised areas, their transport to downstream systems by meltwater will eventually reduce as glacial ice volume shrinks. These effects will profoundly influence the natural environment and the ecosystem services that glacier-fed rivers provide to humans, particularly provision of water for agriculture, hydro-power and consumption.

Among the major impacts, there are profound changes to ecosystem function and services via alteredprovision of water resources and reorganisation of the regulatory processes that shape water quality and geohazards.

CLIMATE CHANGE

Deforestation contributes more

When it comes to tackling climate change, the focus often falls on reducing the use of fossil fuels and developing sustainable energy sources. But a new study shows that deforestation and subsequent use of lands for agriculture or pasture, especially in tropical regions, contribute more to climate change than previously thought. The new paper published in Environmental Research Letters, also shows just how significantly that impact has been underestimated.

Even if all fossil fuel emissions are eliminated, if current tropical deforestation rates hold steady through 2100, there will still be a 1.5°C increase in global warming. While the carbon dioxide collected by trees and plants is released during the cutting and burning of deforestation, other greenhouse gases — specifically nitrous oxide and methane — are released after natural lands have been converted to agricultural and other human usage.

These gases compound the effect of the carbon dioxide’s ability to trap the sun’s energy within the atmosphere. This contributes to radiative forcing — energy absorbed by earth versus energy radiated off — and a warmer climate. As a result, while only 20% of the rise in carbon dioxide caused by human activity originates from land use and land-cover change, the warming proportion from land use increases to 40% once co-emissions like nitrous oxide and methane are factored in.

POSITIVE REACTION

Before hunting, wild dogs sneeze

When they want to move as a group, meerkats call to each other. Capuchin monkeys trill. Gorillas grunt.

African wild dogs sneeze. And that’s a first. For one thing, it seems to indicate a positive reaction to a proposal before a group of dogs. When a pack of these dogs is getting ready to hunt, scientists recently reported that the more sneezes, the more likely they are to actually get moving.

Almost all social organisms make group decisions that require reaching a consensus. However, among the grunts, huffs and others, the sneeze had not been reported as one of those signals until a group of researchers published their observations of African dogs in the Proceedings of the Royal Society B.

INDEPENDENT IN GROUPS

Individuality drives group dynamics

For centuries, scientists and non-scientists alike have been fascinated by the beautiful and often complex collective behaviour of animal groups. In a new paper in the journal Current Biology, a team of researchers have suggested that individual characteristics play a fundamental role in the dynamics and functioning of social groups.

To understand how much influence individuals have over the collective behaviour of the group, the researchers tested the individual stickleback fish in different behavioural assays and then exposed them in groups to a range of ecological environments. They found that fish that tended to spent more time near others actually had lower individual speeds, had more central positions in the group, and were much more likely to follow in the freely swimming shoals.

SOPHISTICATED STRATEGY

Organising nuts by favourite

Like trick-or-treaters sorting their Halloween candy haul, fox squirrels apparently organise their stashes of nuts by variety, quality and possibly even preference, according to a new study published in the Royal Society Open Science journal. The study shows that squirrels arranging their bounty using ‘chunking’, a cognitive strategy in which humans and other animals organise spatial, linguistic, numeric or other information into smaller more manageable collections, such as subfolders on a computer.

Fox squirrels stockpile at least 3,000 to 10,000 nuts a year and, under certain conditions, separate each cache into quasi ‘subfolders’, one for each type of nut, researchers said. Presumably, sophisticated caching techniques maximise the squirrels’ ability to remember where they’ve stored their most prized treats while at the same time hiding them from potential pilferers, the researchers said.

DOCUMENTARY

Saving Amur falcons

In Nagaland, a small team of conservationists stumbled upon a vast congregation of Amur falcons around a remote reservoir being captured and slaughtered by local hunters.

The Race to Save the Amur Falcon looks at the investigation that followed, and the campaign that was launched to save the falcons. To watch it, visit www.bit.ly/2f7fwMk.

The autumnal equinox

The autumnal equinox is one of two moments during the year during which the sun aligns directly over the equator. Many mark it as the first day of the fall. It will occur on this date in the Northern Hemisphere, and on March 20 in the Southern Hemisphere.

The autumnal equinox is one of two moments during the year during which the sun aligns directly over the equator. Many mark it as the first day of the fall. It will occur on this date in the Northern Hemisphere, and on March 20 in the Southern Hemisphere. of the fall. It will occur on this date in the Northern Hemisphere, and on March 20 in the Southern Hemisphere.a fasf

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(Published 20 September 2017, 05:28 IST)

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