Showing papers on "Global warming published in 1989"

The Greenhouse Effect: Science and Policy

Abstract: Global warming from the increase in greenhouse gases has become a major scientific and political issue during the past decade That infrared radiation is trapped by greenhouse gases and particles in a planetary atmosphere and that the atmospheric CO(2) level has increased by some 25 percent since 1850 because of fossil fuel combustion and land use (largely deforestation) are not controversial; levels of other trace greenhouse gases such as methane and chlorofluorocarbons have increased by even larger factors Estimates of present and future effects, however, have significant uncertainties There have also recently been controversial claims that a global warming signal has been detected Results from most recent climatic models suggest that global average surface temperatures will increase by some 2 degrees to 6 degrees C during the next century, but future changes in greenhouse gas concentrations and feedback processes not properly accounted for in the models could produce greater or smaller increases Sea level rises of 05 to 15 meters are typically projected for the next century, but there is a small probability of greater or even negative change Forecasts of the distribution of variables such as soil moisture or precipitation patterns have even greater uncertainties Policy responses range from engineering countermeasures to passive adaptation to prevention and a "law of the atmosphere" One approach is to implement those policies now that will reduce emissions of greenhouse gases and have additional societal benefits Whether the uncertainties are large enough to suggest delaying policy responses is not a scientific question per se, but a value judgment

The "greenhouse" effect and climate change

Abstract: The presence of radiatively active gases in the Earth's atmosphere (water vapor, carbon dioxide, and ozone) raises its global mean surface temperature by 30 K, making our planet habitable by life as we know it. There has been an increase in carbon dioxide and other trace gases since the Industrial Revolution, largely as a result of man's activities, increasing the radiative heating of the troposphere and surface by about 2 W m -2. This heating is likely to be enhanced by resulting changes in water vapor, snow and sea ice, and cloud. The associated equilibrium temperature rise is estimated to be between 1 and 2 K, there being uncertainties in the strength of climate feedbacks, particularly those due to cloud. The large thermal inertia of the oceans will slow the rate of warming, so that the expected temperature rise will be smaller than the equilibrium rise. This increases the uncertainty in the expected warming to date, with estimates ranging from less than 0.5 K to over 1 K. The observed increase of 0.5 K since 1900 is consistent with the lower range of these estimates, but the variability in the observed record is such that one cannot necessarily conclude that the observed temperature change is due to increases in trace gases. The prediction of changes in temperature over the next 50 years depends on assumptions concerning future changes in trace gas concentrations, the sensitivity of climate, and the effective thermal inertia of the oceans. On the basis of our current understanding a further warming of at least 1 K seems likely. Numerical models of climate indicate that the changes will not be uniform, nor will they be confined to temperature. The simulated warming is largest in high latitudes in winter and smallest over sea ice in summer, with little seasonal variation in the tropics. Annual mean precipitation and runoff increase in high latitudes, and most simulations indicate a drier land surface in northern mid-latitudes in summer. The agreement between different models is much better for temperature than for changes in the hydrological cycle. Priorities for future research include developing an improved representation of cloud in numerical models, obtaining a better understanding of vertical mixing in the deep ocean, and determining the inherent variability of the ocean-atmosphere system. Progress in these areas should enable detection of a man-made "greenhouse" warming within the next two decades.

Reconstructed Northern Hemisphere annual temperature since 1671 based on high-latitude tree-ring data from North America

Abstract: Annual Northern Hemisphere surface temperature departures for the past 300 yr were reconstructed using eleven tree-ring chronologies from high-latitude, boreal sites in Canada and Alaska, spanning over 90 degrees of longitude. This geographic coverage is believed to be adequate for a useful representation of hemispheric-scale temperature trends, as high northern latitudes are particularly sensitive to climatic change. We also present a reconstruction of Arctic annual temperatures. The reconstructions show a partial amelioration of the Little Ice Age after the early 1700's, an abrupt, severe renewal of cold in the early 1800's and a prolonged wanning since approximately 1840. These trends are supported by other proxy data. Similarities and differences between our Northern Hemisphere reconstruction and other large-scale proxy temperature records depend on such factors as the data sources, methods, and degree of spatial representation. Analyses of additional temperature records, as they become available, are needed to determine the degree to which each series represents fluctuations for the entire hemisphere. There appear to be relationships between trends observed in our Northern Hemisphere reconstruction and certain climatic forcing functions, including solar fluctuations, volcanic activity and atmospheric CO2. In particular, our reconstruction supports the hypothesis that the global warming trend over the past century of increasing atmospheric CO2 has exceeded the recent level of natural variability of the climate system.

Environmental and economic implications of rising sea level and subsiding deltas: the Nile and Bengal examples.

Abstract: The sea level could increase 02 or 22 by 2100 hinging on the effects of carbon dioxide and chlorofluorocarbons on atmospheric temperature changes parallel heat transfer to and thermal expansion of the ocean more precipitation and melting of polar ice Local sea level increases also depend on subsidence Normally deposition of sediment equalizes delta subsidence Yet many activities change this balance including channeling diverting or damming rivers; destruction of mangrove forests; and removal of groundwater or hydrocarbons Large increases in local sea level are a problem especially for low lying deltas with a large human population 80% of Bangladesh comprises the Bengal Delta Annual floods can cover as much as 35% of the entire country India has diverted flow from the Ganges causing rising salinity in coastal streams in Bangladesh Considerable drilling of shallow and deep wells has resulted in subsidence of twice the normal rate Destruction of mangrove forests increases coastal erosion in Bangladesh In Egypt almost all the productive land and most of the population are located in the Nile Delta The coast has an almost endless band of 1-5 m dunes which could protect Egypt against a sea level rise but the Aswan Low and High dams have prevented the deposition of sediment in the Delta leading to coastal erosion They have also ceased the freshwater influx to the delta causing increased salinization of soils This in turn increases the demand for drilling shallow and deep wells and the increased removal of groundwater hastens subsidence By 2100 local sea level rises of these 2 deltas may be as high as 33 45 m This could result in the loss of 26% of habitable land in Egypt and 34% in Bangladesh Rising sea levels would worsen environmental and economic effects Future coastal and fluvial planning for all areas with low lying deltas and large rivers should consider these scenarios

Global climate change and agriculture: an economic perspective

Abstract: Climate change and related global concerns dominate the current environmental agenda, as evidenced by the recent wave of articles, symposia, workshops, and other scientific and lay forums dealing with this issue. While most atmospheric scientists agree that a climate change "signal" has yet to be detected, concern over potential climate change arising from increasing concentrations of carbon dioxide (CO2), methane (CHF), chlorofluorocarbons (CFCs) and other "greenhouse" gases is motivating substantial funding increases for such research. Climate change is thus likely to be a major research and policy issue well into the next decade.

The changing climate.

Abstract: The scientific community is in agreement that carbon dioxide (CO2) and other gas increases will lead to increases in heat trapping and warm the climate i.e. the greenhouse effect. Questions remain about the extent of the effect and the time span and the geographical location of the climate changes; also when and to what extent should policy intercede. The objective is to provide an understanding of what is known both in its entirety partially and not at all. Examples of both circumstantial and direct evidence from the geologic and historical past are given to show how climate changes interact with fluctuations in greenhouse gases. The examples include atmospheric changes when life evolved and the warmth of the Mesozoic era the climate changes of the ice ages the interglacial period and the past 100 years. Global warming has not followed a steady pattern of increase. In forecasting the future projecting emission is necessary based on the projection of global consumption of fossil fuels and the rate of deforestation which amounts to 50% of the buildup since 1800 and 20% currently. Projected fuel use is dependent on population growth. Typical estimates of global fossil fuel consumption are .5 and 2%/year over the next 20 years. Altogether methane the chlorofluorocarbons nitrogen oxides and low level ozone gases could be equal to CO2 emissions. Projection of other gas emissions is complicated. Another issue discussed is the CO2 rate of uptake which is interrelated with atmospheric concentration changes i.e. rapid climate change could trigger slower forest absorption rates and a warmer climate could speed the release of CO2 from dry soils and methane from wetlands and rice paddies. The correlation between CO2 and temperature is graphically depicted between 1860-2000. An estimate of CO2 atmospheric concentration is 600 parts/million between 2030-80. Models of how this buildup affects climate are presented. Changes could significantly affect agriculture and human settlements. The response to the threats identified could be to use technical measures to counteract climate change to adapt actively or passively or to curtail CO2 buildup. Proposals for immediate action are presented and involve hundreds of billions of dollars.

Global Warming: Are We Entering the Greenhouse Century?

Abstract: "How important is a degree of temperature change? A degree or two temperature change is not a trivial number in global terms and it usually takes nature hundreds of thousands of years to bring it about on her own. We may be doing that in decades ...Humans are putting pollutants into the atmosphere at such a rate that we could be changing the climate on a sustained basis some ten to a hundred times faster than nature has since the height of the last ice age." - Stephen H. Schneider This essential book examines the causes of world-wide climatic change - the 'greenhouse effect' - that may raise world temperatures by five degrees Celsius in less than a century. Author Stephen H. Schneider describes the likely consequences - from agricultural changes and rises in sea level to public health issues and social upheaval - and addresses the most important and urgent question that anyone concerned with the fate of our planet must confront: 'What can or should be done about the greenhouse effect?' "Global Warming" offers a prophetic look at a year in the greenhouse century, one of slowly increasing global temperatures (a century that may have already begun). The immediate scenarios are grave: population pressures combined with devastating floods and hurricanes drive millions of 'environmental refugees from South East Asia to find homes in Australia; California smothers under heat, smog, water shortages, and raging forest fires; and New York experiences summer heat waves so intense that hospital emergency rooms are jammed with victims. The outlook for Britain could be equally serious: the UN predicts that global warming may cause severe winter storms, the flooding of coastal defences, and even malaria in Southern England. Dr Schneider provides and authoritative and entertaining look at the science, personalities and politics behind the problem of global warming. He explains in clear, non-technical language what is scientifically well known, what is speculative, and where the major uncertainties lie. He presents an overview of sixty million years of global climate history, explaining the mechanisms that regulate climate, demonstrates how a few degrees variation can precipitate dramatic evens such as the Ice Age, and discusses how predictions are made by computer modelling to anticipate climatic changes into the next century. "Global Warming" provides a revealing inside look at the problems scientists encounter in dealing with other scientists, politicians and the media. Although statesmen have called for a giant international effort to tackle the issue, few concrete measures have been taken so far. Global Warming outlines the ways individuals, governments and businesses can work together to slow down the damage our impact has inflicted on the planet, and help make global development more environmentally sustainable.

Reconstruction of tree-line vegetation response to long-term climate change

Abstract: KNOWLEDGE of the vegetation response to climate change is necessary to assess and predict realistic ecosystem development in the anticipated, CO2-induced warmer world, particularly at high latitudes where greater warming is expected1–3. Reconstruction of vegetation development over the past 1,000 years may be helpful in this respect, because this period was characterized by contrasting climatic conditions4–9. Here we report the reconstruction of wind-exposed, tree-line vegetation associated with long-term climate change in northern Canada, using tree-ring and growth-form analyses of spruce subfossils. Three major types of growth form within the exposed, but stable, lichen–spruce community successively predominated in response to climate forcing: high krummholz (dwarf spruce, 2–3 m high) and high krummholz (AD 1435–1570, warm period) and low krummholz ( ≲50 cm) (little ice age to present: AD 1570 onwards, cold period and present climate, respectively). Whereas the expansion of a marginal lichen–spruce woodland climaxed during the late Middle Ages (AD 1435–1570), present development of a low-krummholz vegetation at these sites seems to be out of phase with the twentieth century warming. This suggests that ecosystem recovery to global warming is not straightforward, depending on the nature of vegetation structure present at the time climate change occurred. The implications of such ecosystem resilience for the detection and monitoring of the expected CO2-induced warming is discussed, particularly for the climate-sensitive arctic and subarctic regions.

Forests: a tool to moderate global warming

Abstract: Earth's climate may be growing warmer in response to atmospheric accumulation of greenhouse gases, predominantly but not exclusively stemming from human-induced emissions of carbon dioxide (CO/sub 2/) into the atmosphere. Once in the atmosphere, CO/sub 2/ traps heat that would otherwise radiate into space. Each year the Earth's atmosphere takes up approximately 2.9 billion tons of the 4.8 to 5.8 billion tons of carbon that are emitted from various sources. The rest is removed from the atmosphere by natural processes in carbon sinks - places like oceans or forests where carbon is removed from the atmosphere and stored. In addition, changes in land use that have eliminated terrestrial biomass, including tropical forests, have released into the atmosphere the carbon that was captive in the vegetation. Humankind can respond to the prospective global climate change by adapting to the warming, attempting to limit the warming by preventing or mitigating the buildup of atmospheric carbon, or by some combination of the above. Forests can play a critical role in any attempt to mitigate the warming because they are able to capture and store large amounts of carbon from the atmosphere.

Energy policy in the greenhouse

Abstract: This book discusses the problems of global warming. The authors start with an analysis of the driving forces of the greenhouse effect and develop a budget for future carbon dioxide releases to meet specified limits on the risks of human-induced climate change. They also provide guidelines for the formulation of an international convention on climate stabilization and sustainable development.

Climate-induced feedbacks for the global cycles of methane and nitrous oxide

Abstract: Recent experiments have shown that the concentrations of methane dipped to between 300 and 350 ppbv during the ice ages some 20,000 and 150,000 years ago. Our data, spanning more recent times, show a proportionate decrease of methane (38 ± 19 ppbv) and also a decrease of nitrous oxide (about 6 ± 4 ppbv) during the little ice age between 1450 and 1750 AD. We believe that these decreases are a measure of the response of emissions from the earth's soils, oceans, and wetlands to global climatic change. In the future, as the earth warms from increasing levels of carbon dioxide, methane, nitrous oxide, and other trace gases, these feedbacks may produce more and more methane and nitrous oxide. Melting of the upper layers of permafrost in the high arctic could add still more methane and nitrous oxide to the atmosphere. The combination of the response of wetlands and permafrost may add as much or more methane and nitrous oxide to the atmosphere as expected from the increasing anthropogenic sources. Since adding methane is about 20 times more effective in increasing global temperatures as adding equal amounts of carbon dioxide, and nitrous oxide is perhaps more than 200 times as effective, even small increases in the emissions of these gases could be amplified into large effects on the earth's temperature and climate. The global warming that has apparently occurred over the past century may already have produced about 20% of the increase of nitrous oxide between the pre-industrial times and the present. DOI: 10.1111/j.1600-0889.1989.tb00141.x

Some northern sources of atmospheric methane: production, history, and future implications

Abstract: Northern sources, including wetlands and perhaps gas hydrates, contribute significantly to the CH4 content of the atmosphere. Methane production from northern wetlands, including bogs, swamps, and ponds, is probably very seasonal, being most important in late summer, with significant evasion in autumn as lakes overturn. The strong recovery of beaver populations in Canada, from near-extinction 50 years ago to present abundance, may also be important, both in creating new wetlands and in the alteration of them; wetlands that have been altered by beaver activity produce orders of magnitude more methane than beaver-free wetlands. In the Arctic, methane gas hydrates represent a significant source of methane, which may become more important if Arctic warming occurs as part of global climate change. The danger of a thermal runway caused by CH4 release from permafrost is minor, but real. Other high-latitude sources of CH4 include Arctic peat bogs, and losses from natural gas production, especially in the Soviet U...

Upper ocean temperature variability in the northeast Pacific Ocean: Is it an indicator of global warming?

Abstract: The upper waters of the Northeast Pacific Ocean contain very low frequency temperature fluctuations which have amplitudes of more than 1°C. Hydrographic measurements at 60°N, 149°W, and sea surface temperatures (SST) on a 5° grid over the Northeast Pacific are used to examine these variations. The very low frequency (VLF) 20- to 30-year fluctuation in SST found at and north of 55°N is not evident at lower latitudes. This VLF fluctuation exists throughout the water column on the shelf of the northern Gulf of Alaska. Contained within the hydrographic data on the shelf are responses to El Nino-Southern Oscillation (ENSO) forcing. However, ENSO responses are not evident in the SST data. The propagation characteristics of SST anomalies through the region are not consistent from one event to another. One SST anomaly moved eastward through the region over a 3-year period (1956–1959), whereas the 1983 anomaly appeared simultaneously throughout the Gulf of Alaska. Correlations with local wind stress and wind stress curl are very poor, implying that the temperature variability is not wind forced. The causes for these temperature anomalies are uncertain. Though climate changes due to increases in greenhouse gases might be amplified at high latitudes, heating due to global warming is discounted. Coupling of the temperature fluctuations with solar activity and lunar tides is possible especially at high latitudes and the periods of the temperatures, tides, and solar activity are well matched. In any case, the recent upper ocean warming is probably not a result of large-scale global change but is, rather, part of the VLF zonal signal. Below normal water and air temperatures should occur over the next 5–15 years. This VLF signal must be considered and understood before we will be able to measure the effects of high-latitude climate changes.

Slowing global warming: a worldwide strategy

Abstract: This paper reviews the evidence for global warming and the greenhouse effect, then outlines a credible global warming action plan. The author sees two key elements of such a plan: (1) reversing the destruction of the world's tropical forests; and (2) eliminating the production and use of chlorofluorocarbons within the next decade. While the challenge is a daunting one, the author's opinion is that climate change is a problem with which humanity still has the ability to cope. However, he believes that time is short if we are to avoid a cataclysmic warming. Section headings include the following: In Defense of the Atmosphere; The Threat of Climate Change; Cooling the Greenhouse; The Shape of a New Energy Future; A Greenhouse Policy Agenda; and The International Challenge.

Greater global warming revealed by satellite-derived sea-surface-temperature trends

Abstract: INVESTIGATING the response of global climate to changes in external forcing is essential to our understanding of climate change. Here I present an analysis of satellite-derived sea surface temperatures for the period 1982–88. It can be seen from this analysis that the global ocean is undergoing a gradual but significant warming of ˜0.1 °C per year, whereas the trend obtained for the same period from conventional data sources (ships and buoys) is about half that magnitude1. Satellite global coverage, however, is far greater and, although we have no long time series of satellite data (as opposed to conventional data), it is possible to observe short-term trends, as shown here, that may not be discerned using the coarser-resolution conventional data.

Potential Effects of Global Climate Change on the United States. Appendix H. Infrastructure. Report to the Congress

Abstract: This appendix contains back-up research studies for The Potential Effects of Global Climate Change on the United States report for Congress (1989).

Sensitivity of tropospheric hydrogen peroxide to global chemical and climate change

Abstract: The sensitivities of tropospheric HO2 and hydrogen peroxide (H2O2) levels to increases in CH4, CO, and NO emissions and to changes in stratospheric O3 and tropospheric O3 and H2O have been evaluated with a one-dimensional photochemical model. Specific scenarios of CH4-CO-NO(x) emissions and global climate changes are used to predict HO2 and H2O2 changes between 1980 and 2030. Calculations are made for urban and nonurban continental conditions and for low latitudes. Generally, CO and CH4 emissions will enhance H2O2; NO emissions will suppress H2O2 except in very low NO(x) regions. A global warming or stratospheric O3 depletion will add to H2O2. Hydrogen peroxide increases from 1980 to 2030 could be 100 percent or more in the urban boundary layer.

Global Climate Change: Predictions and Observations

Abstract: There are only three certainties concerning the current issue of global climate change: (a) trace gases which absorb longwave infrared radiation in the earth's atmosphere are increasing due to anthropogenic activities; (b) increases in absorption of longwave radiation are likely to alter the earth's energy balance, leading to warming of the earth's surface; and (c) global surface air temperature are rising Beyond these three incontrovertible statements, uncertainties multiply as to causality of observed warming, magnitude and rate of change of potential warming, effects on the hydrological cycle, regional specification of change, and, finally, impacts of the projected changes on biological, physical, and economic systems

Changing climate and permafrost distribution in the soviet arctic

Abstract: Anticipated global warming during the next century will produce many environmental changes, including widespread thawing of permafrost in the northern hemisphere. A nonstationary model of heat and water transport in a stratified medium was used in conjunction with results from a climate-change model to estimate the severity of permafrost degradation. Results suggest that the area of continuous permafrost in the USSR may be reduced by 15 to 20% over a 50-year period.

Climate and energy : the feasibility of controlling CO[2] emissions

Abstract: Rapidly increasing concentrations of greenhouse gases in the atmosphere, emerging evidence of global warming and the threat of uncontrollable climate feedback mechan: i, sms are now triggering international action to reduce the emissions of greenhouse gases. In 1989 the Intergovernmental Panel on Climate Change (IPCC), established by the United Nations Environment Pro gramme and the World Meteorological Organization, started preparations for an international convention on climate. This convention is to be followed by protocols (agreements) on the reduction of the emissions of greenhouse gases and other measures and implementation mechanisms to preserve the global climate. After the CFC's, CO is the next in line, as the sources 2 and abatement measures for CH and N 0 are as yet insuffi 4 2 ciently understood. However, the abatement of CO . is a far 2 reaching issue. It will require major changes wi thin the most important sectors of the economy: energy (production and use) and agriculture (deforestations and land use pat terns). Given this situation it is not so surprising that national governments are hesitant to take action. One reason is the remaining uncertainty regarding the rat, e and the extent of climate change. However, further analysis will show that the uncertainties will be outweighed by the increasing risks when measures to reduce the emission of greenhouse gases are delayed."

Adapting water resources management to global climate change

Abstract: This paper provides an overview of the impact of global climate change on water resources management. Changes in precipitation and temperature of the scale predicted by General Circulation Models for a doubled CO2 level will significantly affect annual runoff, runoff variability, and seasonal runoff. These in turn will affect water supply, flood protection, hydropower generation, and environmental resources. In addition, climate change will significantly affect the geomorphic response of the watershed, increasing soil erosion and altering the hydrologic response of the watershed. These geomorphic changes will in turn affect water supply, flood hazard, and riparian ecosystems. Possible water resources management responses are identified. This includes reallocation of water supply from less valuable irrigated agriculture to municipal uses; changes in agricultural methods; increasing incentives for integrated flood management; increasing incentives for watershed management; integration of ecosystem needs in water resources planning; and the need to redesign the operation of existing water projects.

Climate and geo-sciences : a challenge for science and society in the 21st century

Abstract: Section 1 - Climate Record / What can We Learn from Data ?- Pre-Pleistocene climates : data and models- Archaean atmosphere-biosphere interactions- Dating proxy data- The spectral characteristics of pre-Quaternary climatic records, an example of the relationship between the astronomical theory and Geo-Sciences- Polar ice cores and climate- Intermediate and deep water characteristics during the last glacial maximum- Oceanic response to orbital forcing in the late Quaternary : observational and experimental strategies- Recent developments in Quaternary paleoclimatology- Paleoclimate data for studies of global climate change and earth system science- Paleoclimate perspectives on a greenhouse warming- Section 2 - Understanding Climate and Climatic Changes- Deceptively-simple models of climatic change- Climate predictability : a dynamical view- Coupled ocean and sea-ice models : review and perspectives- Atmospheric chemistry - climate interactions- Ice and climate studies- Volcanoes and climate- Global climatic effects of a nuclear war: an interdisciplinary problem- Land surface processes in climate models : status and prospects- Tropical deforestation and climatic change- The role of the hydrological cycle in climate- Changes in ocean temperature and the scientific strategy for international climate research- Section 3 - Simulation of the Greenhouse Warming- Model projections of the climatic changes induced by increased atmospheric CO2- Climate sensitivity : model dependence of results- Climate response to greenhouse warming : the role of the ocean- Unresolved issues and research needs pertaining to the transient climatic response to a CO2 increase- Global biogeochemical cycles and climate- Anthropogenic and natural perturbations of the carbon cycle- Modelling biospheric control of carbon fluxes between atmosphere, ocean and land in view of climatic change- Section 4 - Technology for Climate Studies- Supercomputing and massive parallelism- Data management methods data for Europe- Satellites and climate- Radiation budget and clouds- Section 5 - Climate Environment and International Security- The global commons and national security- The global environmental issues - an approach to their solution- Human impact on the environment- Society and future climate change- Global climatic changes and geopolitics: pressures on developed and developing countries- Climate change in the context of multiple threats- Climate and public policy in the United States Congress- Climatic changes and water resources development- Hydrological impacts - What if we are right ?- Climate change : effects on biological systems- Forest productivity and health in a changing atmospheric environment- Climate environment in international security: the case of deforestation in the brazilian amazon- Section 6 - Conference Overview and Recommendations- Where is climate research going ?- Authors Index- Subjects Index

Sensitivity of crop yields and land resource potential to climatic change in Ontario, Canada

Abstract: Increasing concentrations of atmospheric CO2 and other greenhouse gases are expected to contribute to a global warming. This paper examines the potential implications of a climatic change corresponding to a doubling of atmospheric concentrations of CO2 on crop production opportunities throughout Ontario, a major food producing region in Canada. The climate is projected to become warmer and drier, but the extent of these shifts are expected to vary from region to region within Ontario. The effect of this altered climate on crop yields and the area of land capable of supporting specific crops varies according to region, soil quality and crop type. Most notable are the enhanced opportunities for grains and oilseeds in the northern regions, and the diminished production prospects for most crops in the most southerly parts of Ontario.

Global change and carrying capacity: Implications for life on Earth

Abstract: Determining the long-term number of people that the planet can support without irreversibly reducing its ability to support people in the future, i.e., the carrying capacity of the Earth, is an exceedingly complex problem. About all that is known for certain is that, with present and foreseeable technologies, the human population has already exceeded the capacity. The reduction in carrying capacity that can be expected to result from direct human impacts on resources and the environment and from our indirect impacts of the climate system is discussed. Global warming and modeling global change and food security are also discussed with respect to carrying capacity.

Testing the Global Warming Hypothesis

Abstract: The temperature record for the global surface air temperature indicates that six of the warmest years occurred in the period 1980–1988. Here we address the question on the likelihood that such an arrangement is simply a manifestation of the natural variability of the system. Our results indicate that the probability that such an arrangement will arise naturally is between 0.010 and 0.032.

Climatic change, rising sea level, and the British coast

Abstract: If current predictions are borne out, a global warming associated with high concentrations of atmospheric pollutants may mean that Britain has some hard choices to make over the next century. A rise in sea levels caused by climatic change could pose a serious threat to the flora and fauna of many coastal areas, and could also affect agricultural uses. This report considers the biological implications of rises of 0.8m up to 1.65m, and examines the different impacts on the coastal environment of various options in sea defence and coast protection. An important and timely report for all ecologists and planners.