Showing papers on "Global warming published in 1986"

Future global warming from atmospheric trace gases

Abstract: Human activity this century has increased the concentrations of atmospheric trace gases, which in turn has elevated global surface temperatures by blocking the escape of thermal infrared radiation. Natural climate variations are masking this temperature increase, but further additions of trace gases during the next 65 years could double or even quadruple the present effects, causing the global average temperature to rise by at least 1 °C and possibly by more than 5 °C. If the rise continues into the twenty-second century, the global average temperature may reach higher values than have occurred in the past 10 million years.

High-Resolution Climatic Analysis and Southwest Biogeography

Abstract: Meteorologists and climatologists have produced significant new data on the fluid dynamics of the atmosphere, thus allowing biologists to examine more closely the cause-effect relation between the large-scale structure of the atmosphere and the dominant patterns of global biogeography The inability to characterize the high-frequency variability of the weather has constrained such efforts A method that allows year-to-year patterns of weather variability to be characterized in the contexts of global warming and cooling trends is applied in a combined analysis of long-term monthly weather records and data from an ecological monitoring project in southern New Mexico The analysis suggests a cause-effect hypothesis of recent desertification in the North American Southwest The links between the atmosphere and the biosphere are based on the fundamentally different responses to specific weather regimes of semidesert grasses with a C(4) photosynthetic pathway and desert shrubs with a C(3) photosynthetic pathway The hypothesis appears to be of sufficient generality to explain the complex, but well-documented, floristic changes that have occurred in the same region since the last glacial maximum

Global climatic trends as revealed by the recorded data

Abstract: Recent results from climate models have led to the prediction that a global warming due to increasing atmospheric CO2 is now imminent, if it has not already occurred. In an effort to develop more definitive information on this question, a detailed review has been conducted of prior efforts to unravel climatic change from the various types of recorded observational data available. Most of the more definitive of the prior analyses—along with evaluative comments by the various authors—have been assembled herein. There appears little doubt that the average surface air temperature of at least northern hemisphere has been increasing since the beginning of recorded data with most of the warming occurring in a brief period circa 1920. The fragmentary early data suggest significant cooling prior to 1883 such that 25–50% of the subsequent warming may represent a return to earlier levels. Whether the overall warming constitutes a climate change remains an unresolved problem, as does the cause of the warming.

Equilibrium and transient climatic warming induced by increased atmospheric CO2

Abstract: The change in the Earth's equilibrium global mean surface temperature induced by a doubling of the CO2 concentration has been estimated as 0.2 to 10 K by surface energy balance models, 0.5 to 4.2 K by radiative-convective models, and 1.3 to 4.2 K by general circulation models. These wide ranges are interpreted and quantified here in terms of the direct radiative, forcing of the increased CO2, the response of the climate system in the absence of feedback processes, and the feedbacks of the climate system. It is the range in the values of these feedbacks that leads to the ranges in the projections of the global mean surface warming. The time required for a CO2-induced climate change to reach equilibrium has been characterized by an e-folding time τe with values estimated by a variety of climate/ocean models as 10 to 100 years. Analytical and numerical studies show that this wide range is due to the strong dependence of τe on the equilibrium sensitivity of the climate model and on the effective vertical thermal diffusivity of the ocean model. A coupled atmosphere-ocean general circulation model simulation for doubled CO2 suggestes that, as a result of the transport of the CO2-induced surface heating into the interior of the ocean, τe ≅ 50 to 100 years. Theoretical studies for a realistic CO2 increase between 1850 and 1980 indicate that this sequestering of heat into the ocean's interior is responsible for the concomittant warming being only about half that which would have occurred in the absence of the ocean. These studies also indicate that the climate sytem will continue to warm towards its as yet unrealized equilibrium temperature change, even if there is no further increase in the CO2 concentration.

Tending the Global Commons

Abstract: This paper reviews the climate, health, and related effects attributable to changes in atmospheric chemistry (carbon dioxide, ozone, chlorofluorocarbons, methane, and other trace gases). Included are discussions of climate change, increases in ultraviolet radiation, rising sea level, policy options, and inter-agency disagreements.

Review of global energy and carbon dioxide projections

Abstract: The concentration of carbon dioxide (CO/sub 2/) in the Earth's atmosphere has risen steadily over the last century, giving rise to the widely publicized ''greenhouse effect,'' believed to be responsible for a gradual warming trend in the Earth's climate. In addition to CO/sub 2/, recent studies have revealed increasing atmospheric concentrations of other ''greenhouse'' gases (e.g. methane, nitrous oxide, and chlorofluorocarbons) that may well exacerbate this warming trend considerably. While the sources of these latest gases have not yet been clearly identified, emissions of CO/sub 2/ into the atmosphere are known to come from anthropogenic sources, primarily the combustion of fossil fuels. Thus an important component in the investigation of future global warming is an understanding of future carbon emissions, which in turn requires a study of future energy developments, particularly fossil fuel consumption. Various attempts have recently been made to project the global energy future and corresponding CO/sub 2/ emissions several decades ahead. This paper provides a critical review of some of these efforts.

The CO 2 climate response problem a statistical approach

Abstract: The anthropogenic increase of the atmospheric carbon dioxide (CO2) concentration leads to a global warming of the atmospheric surface layer, whereas the stratosphere is cooled This “greenhouse” effect postulated by a number of climate models (on a physical basis) can be conditionally verified by statistical multiple regression techniques In this study the following climatic time series are used (all data yearly averages): northern hemisphere mean temperatures near surface 1781–1980 (alternatively since 1851 or 1881) and corresponding stratospheric data 1958–1983, sea surface temperatures 1856–1980, northern hemisphere or global average, alternatively, and the global mean sea level fluctuations 1881–1980 In order to account for an appropriate part of explained variance, volcanic and solar forcing parameters are implied and the data are low-pass filtered suppressing variations of the period rangeT < 10 years Based on the recently assessed preindustrial CO2 concentration of c 280 ppm and the Mauna Loa value of c 344 ppm in 1984 this “industrial” CO2 increase reveals a northern hemisphere temperature increase near surface of c (7±1) K (average and standard deviation of all statistical regression runs), statistically significant at the 95% level A CO2 doubling (300 to 600 ppm) leads to a statistically derived signal of (31±6) K, satisfactorily congruent with the results of most of the (deterministic) climate models: c (3±15)K A stratospheric cooling trend in recent time may be existent but is highly non-significant Similarly, the SST data do not allow to evaluate a significant CO2 signal to noise ratio In contrast to that the observed long-term global mean sea level increase (93 cm) can be predominantly attributed to the CO2 effect (999% level)

Global Tertiary climatic changes, paleophytogeography and phytostratigraphy

Abstract: The most notable mega longtime event in the Tertiary is the global transformation of the climate: the globally warm and equable Mesozoic climate on Earth changes into a globally colder climate. The causes of these climatic changes are extremely complex (various abiotic and biological events in constant mutual interaction).

Can We Slow Global Warming

Abstract: U of M geography professor Steven Manson and his students research human activity and its effects on global environmental change. By generating agent-based modeling, a way to examine how humans alter land surface on the earth, they predict probable environmental consequences of this surface alteration. This research could help avert potentially disastrous changes in climate. Seems like modeling is a model way to slow global warming. So the search continues. Learn more at umn.edu. A cool plan.