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Implications of the Circumpolar Genetic Structure of Polar Bears for Their Conservation in a Rapidly Warming Arctic

February 25, 2015 Comments off

Implications of the Circumpolar Genetic Structure of Polar Bears for Their Conservation in a Rapidly Warming Arctic
Source: PLoS ONE

We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. Characterizing their circumpolar genetic structure using microsatellite data, we defined four clusters that largely correspond to current ecological and oceanographic factors: Eastern Polar Basin, Western Polar Basin, Canadian Archipelago and Southern Canada. We document evidence for recent (ca. last 1–3 generations) directional gene flow from Southern Canada and the Eastern Polar Basin towards the Canadian Archipelago, an area hypothesized to be a future refugium for polar bears as climate-induced habitat decline continues. Our data provide empirical evidence in support of this hypothesis. The direction of current gene flow differs from earlier patterns of gene flow in the Holocene. From analyses of mitochondrial DNA, the Canadian Archipelago cluster and the Barents Sea subpopulation within the Eastern Polar Basin cluster did not show signals of population expansion, suggesting these areas may have served also as past interglacial refugia. Mismatch analyses of mitochondrial DNA data from polar and the paraphyletic brown bear (U. arctos) uncovered offset signals in timing of population expansion between the two species, that are attributed to differential demographic responses to past climate cycling. Mitogenomic structure of polar bears was shallow and developed recently, in contrast to the multiple clades of brown bears. We found no genetic signatures of recent hybridization between the species in our large, circumpolar sample, suggesting that recently observed hybrids represent localized events. Documenting changes in subpopulation connectivity will allow polar nations to proactively adjust conservation actions to continuing decline in sea-ice habitat.

See: Polar Bears Shifting to Areas with More Sea Ice — Genetic Study Reveals (USGS)

Back to the Future: Advanced Nuclear Energy and the Battle Against Climate Change

February 10, 2015 Comments off

Back to the Future: Advanced Nuclear Energy and the Battle Against Climate Change
Source: Brookings Institution

A new Brookings Essay examines innovative nuclear reactor designs that could power the world with nuclear waste and reignite American leadership in the fight against climate change.

Tracing CO2 Emissions in Global Value Chains

February 2, 2015 Comments off

Tracing CO2 Emissions in Global Value Chains (PDF)
Source: U.S. International Trade Commission

This paper integrates two lines of research: trade in global value chains and embodied emissions into a unified conceptual framework. This allows both value-added and emissions to be systematically traced at the country, sector, and bilateral levels through various production network routes. By combining value-added and emissions accounting in a consistent way, the potential environmental cost (emission with per unit of value-added created) along Global Value Chains can be estimated. Based on this unified accounting method, we trace CO2 emission in global production and trade network among 41 economies in 35 sectors from 1995 to 2009 based on the World Input-Output Database (WIOD) database and show how they help us to better understand the impact of cross-country production sharing on the environment.

How climate change could affect corporate valuations

January 30, 2015 Comments off

How climate change could affect corporate valuations
Source: McKinsey & Company

Not surprising, we found that carbon-abatement efforts will put dramatically different levels of stress on the cash flows and valuations of different industries. The level of change for individual public companies within a given sector could of course substantially exceed the average, depending on their current position and their ability to respond to new technologies, changes in consumer behavior, and regulation.

NCDC Releases 2014 Global Climate Report

January 16, 2015 Comments off

NCDC Releases 2014 Global Climate Report
Source: NOAA

The globally averaged temperature over land and ocean surfaces for 2014 was the highest among all years since record keeping began in 1880, according to NOAA scientists. The December combined global land and ocean average surface temperature was also the highest on record.

See also: NASA, NOAA Find 2014 Warmest Year in Modern Record

National Academies Press — Most Downloaded Reports in 2014

January 13, 2015 Comments off

Who Will Come to Your Bird Feeder in 2075?

December 24, 2014 Comments off

Who Will Come to Your Bird Feeder in 2075?
Source: USGS/PLoS ONE

The distribution of birds in the United States today will probably look very different in 60 years as a result of climate, land use and land cover changes.

A new U.S. Geological Survey study predicts where 50 bird species will breed, feed and live in the conterminous U.S. by 2075. While some types of birds, like the Baird’s sparrow, will likely lose a significant amount of their current U.S. range, other ranges could nearly double. Human activity will drive many of these shifts. The study was published today in the journal PLOS ONE.

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