Just imagine

Monthly and 3-hourly precipitation data from twentieth-century climate simulations by the newest generation of 18 coupled climate system models are analyzed and compared with available observations. The characteristics examined include the mean spatial patterns, intraseasonal-to-interannual and ENSO-related variability, convective versus stratiform precipitation ratio, precipitation frequency and intensity for different precipitation categories, and diurnal cycle.

Melting Himalayan glaciers are threatening to unleash a torrent of floods into mountain valleys, and ultimately dry up rivers across South Asia. A new study, due to be presented in July to the International Commission on Snow and Ice (ICSI), predicts that most of the glaciers in the region will vanish within 40 years as a result of global warming.

Global climate change is today a spectre which allows for no ostriches. Scientific data is piling up to indict human activity as the source of the current phase of warming. The debate is whether the affluent North or the developing South has been more responsible and who will be polluting more in the near future.

This document contains the summary for Policymakers: The Science of Climate Change - IPCC Working Group I.

It details the following key features:
1. Greenhouse gas concentrations have continued to increase
2. Anthropogenic aerosols tend to produce negative radiative forcings
3. Climate has changed over the past century

A 4.80 m long shallow water sediment core, collected from the inner shelf (at 22 m water depth) off Karwar, near Kali river mouth is studied for foraminiferal tracers of palaeomonsoons. The climate history of this core which represents the last 4,500 years approximately revealed the evidences of a significant change in the intensity of the precipitation around 2,000 years BP.

Observations made during the 1987 El Niño show that in the upper range of sea surface temperatures, the greenhouse effect increases with surface temperature at a rate which exceeds the rate at which radiation is being emitted from the surface. In response to this 'super greenhouse effect', highly reflective cirrus clouds are produced which act like a
thermostat, shielding the ocean from solar radiation. The regulatory effect of these cirrus clouds may limit sea surface temperatures to less than 305 K.

The NASA Earth Radiation Budget Experiment (ERBE), flying aboard multiple satellites, is providing new insights into the climate system. Monthly averaged clear-sky and cloudy sky flux data derived from the ERBE are used to assess the impact of clouds on the Earth's radiation balance. This impact is examined in terms of three quantities: longwave,
shortwave, and net cloud forcing. Overall, clouds appear to cool the Earth-atmosphere system.

Records of hemispheric average temperatures from land regions for the past 100 years provide crucial input to the debate over global warming.

The study of climate and climate change is hindered by a lack of information on the effect of clouds on the radiation balance of the earth, referred to as the cloud-radiative forcing. Quantitative estimates of the global distributions of cloud-radiative forcing have been obtained from the spaceborne Earth Radiation Budget Experiment (ERBE) launched in
1984.

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