Plant growth and climate change

‘Climate change’ is an all-embracing subject: increasingcarbon dioxide concentration in the atmosphere, due to the insatiableappetite of our burgeoning Homo sapiens (or perhaps better H.carbonovorum) populations for energy from fossil carbon reserves,is the main driver. The consequent global warming may lead tovery complex     

Carbon biogeochemistry and climate change

The rapid increase of atmospheric CO₂ resulting from anthropogenic activites has stimulated a great deal of interest in the carbon cycle. Important decisions need to be made about future tolerable levels of atmospheric CO₂ content, as well as the land and fossil fuel use strategies that will permit us to achieve these goals. The vast amount of new data on atmospheric CO₂ content and ancillary properties that has become available during the last decade, and the development of models to interpret these data, have led to significant advances in our capacity to deal with such issues. However, a major continuing source of uncertainty is the role of photosynthesis in providing a sink for anthropogenic emissions. It is thus appropriate that a new evaluation of the status of our understanding of this issue should be made at this time.The aim of this paper is to provide a setting for the papers that follow by giving an overview of the role of carbon dioxide in climate, the biogeochemical processes that control its distribution, and the evolution of carbon dioxide through time from the origin of the earth to the present. We begin with a discussion of relevant processes. We then proceed to a more detailed discussion of the time periods that are best documented: the late Pleistocene (during which time large continental ice sheets waxed and waned) and the modern era of anthropogenic impact on the carbon cycle.     

Ocean productivity and climate change

Satellite measurements and the development of new techniques have confirmed the importance of ocean biology in controlling the carbon dioxide (CO(2)) content of the atmosphere. The marine sedimentary record shows that climate change and the ocean carbon cycle are closely linked: during glacial periods, marine productivity was enhanced and atmospheric CO(2) levels were reduced. Global warming may have the opposite effect, with reduced uptake of CO(2) exacerbating the problems of climate change.     

全球气候变化与红树林

因为红树林位于海洋与陆地之间,其可能是首先被全球气候变化影响的生态系统。红树林的分布会随着温度气温的升高而增加。全球气候变化对红树林最重要的影响是海平面的变化。随着CO2的增多,大部分的红树林有高的光合作用率、水的利用效率以及生长率。在相对低的光照条件下,红树林的光合作用率相对较高。最后提出了今后尚待加强的一些研究领域。     

Palms tracking climate change

Aim  Many species are currently expanding their ranges in response to climate change, but the mechanisms underlying these range expansions are in many cases poorly understood. In this paper we explore potential climatic factors governing the recent establishment of new palm populations far to the north of any other viable palm population in the world.
Location  Southern Switzerland, Europe, Asia and the world.
Methods  We identified ecological threshold values for the target species, Trachycarpus fortunei , based on gridded climate data, altitude and distributional records from the native range and applied them to the introduced range using local field monitoring and measured meteorological data as well as a bioclimatic model.
Results  We identified a strong relationship between minimum winter temperatures, influenced by growing season length and the distribution of the palm in its native range. Recent climate change strongly coincides with the palm's recent spread into southern Switzerland, which is in concert with the expansion of the global range of palms across various continents.
Main conclusions  Our results strongly suggest that the expansion of palms into (semi-)natural forests is driven by changes in winter temperature and growing season length and not by delayed population expansion. This implies that this rapid expansion is likely to continue in the future under a warming climate. Palms in general, and T. fortunei in particular, are significant bioindicators across continents for present-day climate change and reflect a global signal towards warmer conditions.     

Vulnerability of mires under climate change: implications for nature conservation and climate change adaptation

Wetlands in general and mires in particular belong to the most important terrestrial carbon stocks globally. Mires (i.e. bogs, transition bogs and fens) are assumed to be especially vulnerable to climate change because they depend on specific, namely cool and humid, climatic conditions. In this paper, we use distribution data of the nine mire types to be found in Austria and habitat distribution models for four IPCC scenarios to evaluate climate change induced risks for mire ecosystems within the 21st century. We found that climatic factors substantially contribute to explain the current distribution of all nine Austrian mire ecosystem types. Summer temperature proved to be the most important predictor for the majority of mire ecosystems. Precipitation—mostly spring and summer precipitation sums—was influential for some mire ecosystem types which depend partly or entirely on ground water supply (e.g. fens). We found severe climate change induced risks for all mire ecosystems, with rain-fed bog ecosystems being most threatened. Differences between scenarios are moderate for the mid-21st century, but become more pronounced towards the end of the 21st century, with near total loss of climate space projected for some ecosystem types (bogs, quagmires) under severe climate change. Our results imply that even under minimum expected, i.e. inevitable climate change, climatic risks for mires in Austria will be considerable. Nevertheless, the pronounced differences in projected habitat loss between moderate and severe climate change scenarios indicate that limiting future warming will likely contribute to enhance long-term survival of mire ecosystems, and to reduce future greenhouse gas emissions from decomposing peat. Effectively stopping and reversing the deterioration of mire ecosystems caused by conventional threats can be regarded as a contribution to climate change mitigation. Because hydrologically intact mires are more resilient to climatic changes, this would also maintain the nature conservation value of mires, and help to reduce the severe climatic risks to which most Austrian mire ecosystems may be exposed in the 2nd half of the 21st century according to IPCC scenarios.     

Marine viruses and global climate change

Sea-surface warming, sea-ice melting and related freshening, changes in circulation and mixing regimes, and ocean acidification induced by the present climate changes are modifying marine ecosystem structure and function and have the potential to alter the cycling of carbon and nutrients in surface oceans. Changing climate has direct and indirect consequences on marine viruses, including cascading effects on biogeochemical cycles, food webs, and the metabolic balance of the ocean. We discuss here a range of case studies of climate change and the potential consequences on virus function, viral assemblages and virus-host interactions. In turn, marine viruses influence directly and indirectly biogeochemical cycles, carbon sequestration capacity of the oceans and the gas exchange between the ocean surface and the atmosphere. We cannot yet predict whether the viruses will exacerbate or attenuate the magnitude of climate changes on marine ecosystems, but we provide evidence that marine viruses interact actively with the present climate change and are a key biotic component that is able to influence the oceans' feedback on climate change. Long-term and wide spatial-scale studies, and improved knowledge of host-virus dynamics in the world's oceans will permit the incorporation of the viral component into future ocean climate models and increase the accuracy of the predictions of the climate change impacts on the function of the oceans.     

Bison body size and climate change

The relationship between body size and temperature of mammals is poorly resolved, especially for large keystone species such as bison (Bison bison). Bison are well represented in the fossil record across North America, which provides an opportunity to relate body size to climate within a species. We measured the length of a leg bone (calcaneal tuber, DstL) in 849 specimens from 60 localities that were dated by stratigraphy and ¹⁴C decay. We estimated body mass (M) as M = (DstL/11.49)³. Average annual temperature was estimated from δ¹⁸O values in the ice cores from Greenland. Calcaneal tuber length of Bison declined over the last 40,000 years, that is, average body mass was 37% larger (910 ± 50 kg) than today (665 ± 21 kg). Average annual temperature has warmed by 6°C since the Last Glacial Maximum (~24–18 kya) and is predicted to further increase by 4°C by the end of the 21st century. If body size continues to linearly respond to global temperature, Bison body mass will likely decline by an additional 46%, to 357 ± 54 kg, with an increase of 4°C globally. The rate of mass loss is 41 ± 10 kg per°C increase in global temperature. Changes in body size of Bison may be a result of migration, disease, or human harvest but those effects are likely to be local and short‐term and not likely to persist over the long time scale of the fossil record. The strong correspondence between body size of bison and air temperature is more likely the result of persistent effects on the ability to grow and the consequences of sustaining a large body mass in a warming environment. Continuing rises in global temperature will likely depress body sizes of bison, and perhaps other large grazers, without human intervention.     

Tropical rainforest canopies and climate change

Abstract There is less certainty about the impact of climate change on tropical rainforests than on temperate forests because of the comparative lack of background data and because few large scale experiments have been, and are being, carried out in tropical rainforests. Many of the factors critical to the future of tropical rainforests concern canopies, the key processes that take place there, and the roles and interactions of canopy biodiversity. In particular there are almost no data on how forest canopies and processes are changing with increased carbon dioxide levels. The implications of elevated carbon dioxide, climatic stress and related changes in water‐use efficiency, nutrient availability and other such changes are discussed particularly with references to Australia's tropical rainforests.     

周期性气候变化与人类适应

从古至今,气候变化特别是周期性气候变化,一直深刻影响着人类社会的变革和发展,从旧石器时代人类起源迁移、新石器时代文化文明演变、历史时期王朝兴衰更替,到工业化以来社会经济发展动荡等,无不留下周期性气候变化影响的烙印。本文依据近年来古气候、古人类、环境考古等研究的新证据、新进展,从周期性气候变化的角度审视人类社会各个发展阶段、关键节点的气候特征;通过典型案例,介绍和分析旧石器、新石器、历史时期不同时空尺度周期性气候变化和人类活动之间复杂的相互作用关系,讨论自然科学和人文社会科学对气候变化与人类活动关系认识的异同,阐述在学科交叉背景下研究气候与人类活动关系的新范式。