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Coupling of Vegetation Growing Season Anomalies and Fire Activity with Hemispheric and Regional-Scale Climate Patterns in Central and East Siberia
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An 18-yr time series of the fraction of absorbed photosynthetically active radiation (fAPAR) taken in by
the green parts of vegetation data from the NOAA Advanced Very High Resolution Radiometer
(AVHRR) instrument series was analyzed for interannual variations in the start, peak, end, and length of
the season of vegetation photosynthetic activity in central and east Siberia. Variations in these indicators of
seasonality can give important information on interactions between the biosphere and atmosphere. A
second-order local moving window regression model called the “camelback method” was developed to
determine the dates of phenological events at subcontinental scale. The algorithm was validated by comparing
the estimated dates to phenological field observations. Using spatial correlations with temperature
and precipitation data and climatic oscillation indices, two geographically distinct mechanisms in the system
of climatic controls of the biosphere in Siberia are postulated: central Siberia is controlled by an “Arctic
Oscillation–temperature mechanism,” while east Siberia is controlled by an “El Niño–precipitation mechanism.”
While the analysis of data from 1982 to 1991 indicates a slight increase in the length of the growing
season for some land-cover types due to an earlier beginning of the growing season, the overall trend from
1982 to 1999 is toward a slightly shorter season for some land-cover types caused by an earlier end of season.
The Arctic Oscillation tended toward a more positive phase in the 1980s leading to enhanced high pressure
system prevalence but toward a less positive phase in the 1990s. The results suggest that the two mechanisms
also control the fire regimes in central and east Siberia. Several extreme fire years in central Siberia were
associated with a highly positive Arctic Oscillation phase, while several years with high fire damage in east
Siberia occurred in El Niño years. An analysis of remote sensing data of forest fire partially supports this
hypothesis
VOLUME 20
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Climate-induced changes in the small mammal communities of the Northern Great Lakes Region
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We use museum and other collection records to document large and extraordinarily rapid
changes in the ranges and relative abundance of nine species of mammals in the northern
Great Lakes region (white-footed mice, woodland deer mice, southern red-backed voles,
woodland jumping mice, eastern chipmunks, least chipmunks, southern flying squirrels,
northern flying squirrels, common opossums). These species reach either the southern or
the northern limit of their distributions in this region. Changes consistently reflect
increases in species of primarily southern distribution (white-footed mice, eastern
chipmunks, southern flying squirrels, common opossums) and declines by northern
species (woodland deer mice, southern red-backed voles, woodland jumping mice, least
chipmunks, northern flying squirrels). White-footed mice and southern flying squirrels
have extended their ranges over 225 km since 1980, and at particularly well-studied sites
in Michigan’s Upper Peninsula, small mammal assemblages have shifted from numerical
domination by northern species to domination by southern species. Repeated resampling
at some sites suggests that southern species are replacing northern ones rather than
simply being added to the fauna. Observed changes are consistent with predictions from
climatic warming but not with predictions based on recovery from logging or changes in
human populations. Because of the abundance of these focal species (the eight rodent
species make up 96.5% of capture records of all forest-dwelling rodents in the region and
70% of capture records of all forest-dwelling small mammals) and the dominating
ecological roles they play, these changes substantially affect the composition and
structure of forest communities. They also provide an unusually clear example of change
that is likely to be the result of climatic warming in communities that are experienced by
large numbers of people.
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An Uncertain Future for Soil Carbon
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Predictions of how rapidly the large amounts of carbon stored as soil organic matter will respond to warming
are highly uncertain (1). Organic matter plays a key role in determining the physical and chemical properties of soils and is a major reservoir for plant nutrients. Understanding how fast organic matter in soils can be built up and lost is thus critical not just for its net effect on the atmospheric CO2 concentration but for
sustaining other soil functions, such as soil fertility, on which societies and ecosystems rely. Recent analytic advances are rapidly improving our understanding of the complex and interacting factors that control the age
and form of organic matter in soils, but the processes that destabilize organic matter in response to disturbances (such as warming or land use change) are poorly understood
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Emerging Techniques for Soil Carbon measurements
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Soil carbon sequestration is one approach to mitigate greenhouse gases. However, to reliably
assess the quantities sequestered as well as the chemical structure of the soil carbon, new
methods and equipment are needed. These methods and equipment must allow large scale
measurements and the construction of dynamic maps. This paper presents results from some
emerging techniques to measure carbon quantity and stability. Each methodology has specific
capabilities and their combined use along with other analytical tools will improve soil organic
matter research. New opportunities arise with the development and application of portable
equipment, based on spectroscopic methods, as laser-induced fluorescence, laser-induced
breakdown spectroscopy and near infrared, for in situ carbon measurements in different
ecosystems. These apparatus could provide faster and lower cost field analyses thus
improving soil carbon contents and quality databases. Improved databases are essential to
model carbon balance, thus reducing the uncertainties generated through the extrapolation of
limited data.
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Barking up the Wrong Tree? Forest Sustainability in the wake of Emerging Bioenergy Policies
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The spotted owl controversy revealed that federal forest management policies alone could not guarantee functioning forest ecosystems. At the same time as the owl’s listing, agreements made at the 1992 Rio Earth Summit highlighted the mounting pressures on natural systems, thus unofficially marking the advent of sustainable forestry management (SFM).2 While threats to forest ecosystems from traditional logging practices certainly remain,3 developed and developing countries have shifted generally toward more sustainable forest management, at least on paper, including codifying various sustainability indicators in public laws.4 Nevertheless, dark policy clouds are gathering on the forest management horizon. Scientific consensus has grown in recent years around a new and arguably more onerous threat to all of the world’s ecosystems—climate change. Governments’ responses have focused on bioenergy policies aimed
at curtailing anthropogenic greenhouse gas (GHG) emissions, and mandatesfor renewables in energy supplies now abound worldwide.
[Vol. 37:000
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Amazon Basin climate under global warming: the role of the sea surface temperature
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The Hadley Centre coupled climate–carbon cycle model (HadCM3LC) predicts loss of the Amazon
rainforest in response to future anthropogenic greenhouse gas emissions. In this study, the
atmospheric component of HadCM3LC is used to assess the role of simulated changes in midtwenty-first
century sea surface temperature (SST) in Amazon Basin climate change. When the full HadCM3LC SST anomalies (SSTAs) are used, the atmosphere model reproduces the Amazon Basin climate change exhibited by HadCM3LC, including much of the reduction in Amazon Basin rainfall. This rainfall change is shown to be the combined effect of SSTAs in both thetropical Atlantic and the Pacific, with roughly equal contributions from each basin. The greatest rainfall reduction occurs from May to October, outside of the mature South American monsoon (SAM) season. This dry season response is the combined effect of a more rapid warming of the tropical North Atlantic relative to the south, and warm SSTAs in the tropical east Pacific. Conversely,
a weak enhancement of mature SAM season rainfall in response to Atlantic SST change is suppressed
by the atmospheric response to Pacific SST. This net wet season response is sufficient to prevent dry
season soil moisture deficits from being recharged through the SAM season, leading to a perennial
soil moisture reduction and an associated 30% reduction in annual Amazon Basin net primary
productivity (NPP). A further 23% NPP reduction occurs in response to a 3.58C warmer air
temperature associated with a global mean SST warming.
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Allowable carbon emissions lowered by multiple climate targets
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Climate targets are designed to inform policies that would limit the
magnitude and impacts of climate change caused by anthropogenic
emissions of greenhouse gases and other substances. The target
that is currently recognized by most world governments1 places a
limit of two degrees Celsius on the global mean warming since
preindustrial times. This would require large sustained reductions
in carbon dioxide emissions during the twenty-first century and
beyond2–4. Such a global temperature target, however, is not sufficient
to control many other quantities, such as transient sea level
rise5
, ocean acidification6,7 and net primary production on land8,9.
Here, using an Earth system model of intermediate complexity
(EMIC) in an observation-informed Bayesian approach, we show
that allowable carbon emissions are substantially reduced whenmultiple
climate targets are set. We take into account uncertainties in
physical and carbon cycle model parameters, radiative efficiencies10,
climate sensitivity11 and carbon cycle feedbacks12,13 along with a
large set of observational constraints. Within this framework, we
explore a broad range of economically feasible greenhouse gas scenarios
from the integrated assessment community14–17 to determine
the likelihood of meeting a combination of specific global
and regional targets under various assumptions. For any given
likelihood of meeting a set of such targets, the allowable cumulative
emissions are greatly reduced from those inferred from the temperature
target alone. Therefore, temperature targets alone are unable
to comprehensively limit the risks from anthropogenic emissions.
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Ecologists Report Huge Storm Losses in China’s Forests
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From delicate orchids and magnolias to rare Chinese yews and Kwangtung pines, the flora of Guangdong
Nanling National Nature Reserve is considered so precious that ecologists call the reserve “a treasure trove of species.” But winter storms have reduced the biological hot spot to a splintered ruin. Snow, sleet, and ice laid waste to 90% of the 58,000- hectare reserve’s forests, says He Kejun, director of Guangdong Forestry
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Challenges in the conservation, rehabilitation and recovery of native stream salmonid populations: beyond the 2010 Luarca symposium
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– In May 2010, I chaired a session on challenges to salmonid conservation at the international symposium
‘Advances in the population ecology of stream salmonids’ in Luarca, Spain. I suggested that in addition to scientific challenges, a major challenge will be improving the links between ecologists, conservationists and policy makers. Because the Luarca symposium focused mainly on ecological research, little time was explicitly devoted to conservation. My objective in this paper is to further discuss the role of ecological research in informing salmonid conservation. I begin with a brief overview of research highlights from the symposium. I then use selected examples to show that ecological research has already contributed much towards informing salmonid conservation, but that ecologists will always be faced with limitations in their predictive ability. I suggest that conservation will need to move forward regardless of these limitations, and I call attention to some recent efforts wherein ecological research has played a crucial role. I conclude that ecologists should take urgent action to ensure that their results are availableto inform resource managers, conservation organisations and policy makers regarding past losses and present threats to native, locally-adapted salmonid stocks.
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Climate change impacts on the biophysics and economics of world fisheries
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Global marine fisheries are underperforming economically because of overfishing, pollution and habitat degradation. Added to these threats is the looming challenge of climate change. Observations, experiments and simulation models show that climate change would result in changes in primary productivity, shifts in distribution and changes in the potential yield of exploited marine species, resulting in impacts on the economics of fisheries worldwide. Despite the gaps in understanding climate change effects on fisheries, there is sufficient scientific information that highlights the need to implement climate change mitigation
and adaptation policies to minimize impacts on fisheries.
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