Implications of climate change for agricultural productivity in the early twenty-first century

This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty. Few global-scale assessments have been carried out, and these are limited in their ability to capture the uncertainty in climate projections, and omit potentially important aspects such as extreme events and changes in pests and diseases. There is a lack of clarity on how climate change impacts on drought are best quantified from an agricultural perspective, with different metrics giving very different impressions of future risk. The dependence of some regional agriculture on remote rainfall, snowmelt and glaciers adds to the complexity. Indirect impacts via sea-level rise, storms and diseases have not been quantified. Perhaps most seriously, there is high uncertainty in the extent to which the direct effects of CO₂ rise on plant physiology will interact with climate change in affecting productivity. At present, the aggregate impacts of climate change on global-scale agricultural productivity cannot be reliably quantified.     

Culture collections in the twenty-first century

Culture collections conserve the living tools for biotechnology. Without them there would be no reference organisms, and no stocks of crucial or rare microorganisms that are so valuable for biotechnology and biomedical research. The expertise that drives these collections is under threat, but the collections themselves may survive by pooling their knowledge.     

Plant drugs in the twenty-first century

Lack of effective cooperation among researchers in the applicable biological, physical, and clinical sciences has accounted, in large measure, for the lack of successful development in the United States of any significant number of new plant drugs during the latter part of the 20th century. Unrealistic federal regulations that tend to render unprofitable such research have also played an important role in hindering the development of new plant drugs. It is likely that both of these factors will change in the future as health-conscious consumers demand more accurate information and wider availability of natural drug products. Several anticipated developments will greatly facilitate research and production in this previously difficult area. These include the development of new, simplified bioassay procedures; improved, easily applied analytical methods; and innovative plant-cell-culture methodologies, possibly involving genetic manipulation. The kinds of drugs that need to be developed using such techniques are discussed. It is concluded that significant new plant drugs and new methods of producing them will be developed to serve mankind during the 21st century.     

LCA in Japan in the twenty-first century

The International Journal of Life Cycle Assessment -       

Wetlands and mosquito control in the twenty-first century

Wetlands Ecology and Management - This synthesis is a short introduction to the Wetlands and Mosquito Control special issue of Wetlands Ecology and Management. The geographic extent of the articles...     

Simulating changes in the leaf unfolding time of 20 plant species in China over the twenty-first century

Recent shifts in phenology reflect the biological response to current climate change. Aiming to enhance our understanding of phenological responses to climate change, we developed, calibrated and validated spatio-temporal models of first leaf date (FLD) for 20 broadleaved deciduous plants in China. Using daily meteorological data from the Chinese Meteorological Administration and the Community Climate System Model, version 3 (CCSM3) created using three IPCC scenarios (A2, A1B and B1), we described the FLD time series of each species over the past 50 years, extrapolating from these results to simulate estimated FLD changes for each species during the twenty-first century. Model validation suggests that our spatio-temporal models can simulate FLD accurately with R ² (explained variance) >0.60. Model simulations show that, from 1952 to 2007, the FLD in China advanced at a rate of ?1.14 days decade^?1 on average. Furthermore, changes in FLD showed noticeable variation between regions, with clearer advances observed in the north than in the south of the country. The model indicates that the advances in FLD observed from 1952–2007 in China will continue over the twenty-first century, although significant differences among species and different climate scenarios are expected. The average trend of FLD advance in China during the twenty-first century is modeled as being ?1.92 days decade^?1 under the A2 scenario, ?1.10 days decade^?1 under the A1B scenario and ?0.74 days decade^?1 under the B2 scenario. The spatial pattern of FLD change for the period 2011–2099 is modeled as being similar but showing some difference from patterns in the 1952–2007 period. At the interspecific level, early-leafing species were found to show a greater advance in FLD, while species with larger distributions tended to show a weaker advance in FLD. These simulated changes in phenology may have significant implications for plant distribution as well as ecosystem structure and function.     

American Indians without tribes in the twenty-first century

Among American Indians and Alaska Natives, most aspects of ethnicity are tightly associated with the person's tribal origins. Language, history, foods, land and traditions differ among the hundreds of tribes indigenous to the USA. With this in mind, we ask why almost one million American Indians failed to respond to the tribal affiliation part of the Census 2000 race question. We investigate four hypotheses about why one-third of multiracial American Indians and one-sixth of single-race American Indians did not write any response to the tribal affiliation question: (1) survey item non-response that undermines all fill-in-the-blank questions; (2) a non-salient tribal identity; (3) a genealogy-based affiliation; and (4) a mestizo identity, which does not require a tribe. We use multivariate logistic regression models and high-density restricted-use Census 2000 data. We find support for the first two hypotheses and note that predictors differ substantially for single-race versus multiple-race American Indians.     

Plants and human health in the twenty-first century

The concept of growing crops for health rather than for food or fiber is slowly changing plant biotechnology and medicine. Rediscovery of the connection between plants and health is responsible for launching a new generation of botanical therapeutics that include plant-derived pharmaceuticals, multicomponent botanical drugs, dietary supplements, functional foods and plant-produced recombinant proteins. Many of these products will soon complement conventional pharmaceuticals in the treatment, prevention and diagnosis of diseases, while at the same time adding value to agriculture. Such complementation can be accelerated by developing better tools for the efficient exploration of diverse and mutually interacting arrays of phytochemicals and for the manipulation of the plant's ability to synthesize natural products and complex proteins. This review discusses the history, future, scientific background and regulatory issues related to botanical therapeutics.     

The global nitrogen cycle in the twenty-first century

Global nitrogen fixation contributes 413 Tg of reactive nitrogen (N_r) to terrestrial and marine ecosystems annually of which anthropogenic activities are responsible for half, 210 Tg N. The majority of the transformations of anthropogenic N_r are on land (240 Tg N yr⁻¹) within soils and vegetation where reduced N_r contributes most of the input through the use of fertilizer nitrogen in agriculture. Leakages from the use of fertilizer N_r contribute to nitrate (NO₃⁻) in drainage waters from agricultural land and emissions of trace N_r compounds to the atmosphere. Emissions, mainly of ammonia (NH₃) from land together with combustion related emissions of nitrogen oxides (NO_x), contribute 100 Tg N yr⁻¹ to the atmosphere, which are transported between countries and processed within the atmosphere, generating secondary pollutants, including ozone and other photochemical oxidants and aerosols, especially ammonium nitrate (NH₄NO₃) and ammonium sulfate (NH₄)₂SO₄. Leaching and riverine transport of NO₃ contribute 40–70 Tg N yr⁻¹ to coastal waters and the open ocean, which together with the 30 Tg input to oceans from atmospheric deposition combine with marine biological nitrogen fixation (140 Tg N yr⁻¹) to double the ocean processing of N_r. Some of the marine N_r is buried in sediments, the remainder being denitrified back to the atmosphere as N₂ or N₂O. The marine processing is of a similar magnitude to that in terrestrial soils and vegetation, but has a larger fraction of natural origin. The lifetime of N_r in the atmosphere, with the exception of N₂O, is only a few weeks, while in terrestrial ecosystems, with the exception of peatlands (where it can be 10²–10³ years), the lifetime is a few decades. In the ocean, the lifetime of N_r is less well known but seems to be longer than in terrestrial ecosystems and may represent an important long-term source of N₂O that will respond very slowly to control measures on the sources of N_r from which it is produced.     

Making a difference--women, medicine, and the twenty-first century

Women can and should make a difference in how medical care is given in the future. The increased number of women physicians presents an opportunity to make a significant impact on the quality of medical care. Data is provided on the number of women applicants to medical school, matriculants and graduates, specialty choices, the status of women in academic medicine, and the income of women physicians. Four aspects of the environment that portend important changes for medicine in the future are identified: scientific developments, alternative delivery systems and the corporate practice of medicine, the aging population and other demographic changes, and the expanding number of physicians. Some of these changes suggest opportunities for making a difference in the traditional specialties of medicine, in providing care to underserved populations, in research careers, in the shortage areas of preventive medicine and public health, occupational medicine, child psychiatry, and physical medicine and rehabilitation, and in new areas such as community pediatrics, behavioral pediatrics, and adolescent medicine. There are many choices and many decisions to be made, and each individual can choose to make a difference.     

The use of live apes in research in the twenty-first century

A literature-based survey was conducted on the use of live apes in research between 2000 and 2003. The 599 studies identified and considered were grouped according to area of research, taxonomy and geographic location of the work. The results suggested that behaviour/cognition, conservation and various applications related to virology (most notably, hepatitis and HIV) were the most frequent areas of research. Of the studies, 73% were classified as non-invasive, whereas 27% were classified as invasive. Among the invasive studies, 39% were scored as of mild severity, and 61% were scored as of moderate/substantial severity. Pan species were involved in 65% of the studies, Gorilla species in 15%, Pongo species in 12%, and Hylobates species in 8%. Most of the invasive research was conducted in the USA (60%). The majority of the non-invasive research was conducted in the USA (31%), Japan (13%), or in the animals natural habitats in Africa (35%) and Asia (8%).