The past present and future of global warming and climate change

Inthe Intergovernmental Panel on Climate Change IPCC concluded in its authoritative fifth assessment report that "Warming of the climate system is unequivocal, and since the s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased". Scientists from NASA and other research institutions around the world have been routinely collecting temperature data from a wide number of locations all over the planet.

The past present and future of global warming and climate change

However, both balloon- and satellite-based observations of lower tropospheric temperature over the past two decades actually show a slight cooling trend at the same time that the surface air temperatures have been rising rapidly. The climate modelers have not been able to explain this discrepancy between their model predictions and the actual observations.

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Some climate modeling has been done using estimated variations in Total Solar Irradiance, a broadband measurement of incoming solar energy, which indicate that solar variations are a significant contributor to global warming and climate change.

However, various parts of the solar spectrum vary quite differently than others as a function of time. However, one published climate model study may have approximately incorporated the effects of many of these various spectral changes as a function of time by optimizing their climate model outputs to provide the best possible match between predicted and observed surface air temperature variations.

Figure 1 shows the best climate model result from Soon et al that included input from both solar and greenhouse gas variations. Optimized energy-conservation global climate model result from Soon et al with the best overall fit between observed solid line and predicted dashed line global land surface air temperature variations for the period fromtheir case B3.

Note the extremely good fit between these two curves.

This model result included a heating contribution from variations in solar input Sun and greenhouse gas concentrations GHG. The resulting contribution to the modeled temperature variation from each input is also shown, for GHG dotted line and for the Sun dashdot line.

Adapted from Soon et al It was one of the largest meetings devoted exclusively to climate change ever held in Canada. However, other views suggesting that a considerable fraction of the current warming trend may be caused by changes in ocean circulation, variability of solar output and by natural variability of a complicated nonlinear climate system were also presented.

Variations in solar energy output will undoubtedly help to explain the comings and goings of the ice ages of the recent geologic past and climate change throughout the history of the Earth.

Recent climate changes and predicting the future

If solar variations are the primary driver of recent global warming, which does appear to be the case, then global temperature variations for the rest of the 21st century will depend mostly on what the Sun does next, not on our greenhouse gas emissions. Various predictions of the future course of solar activity indicate that solar heating, on time scales of a decade to a century, has either peaked or will peak shortly and then it will enter a roughly year cooling trend.

The past present and future of global warming and climate change

Therefore, the rapid rise in global surface air temperatures over the last couple of decades may soon come to a natural end if surface solar heating declines as expected. Most paleoclimate data indicate that the warmest period in the present interglacial was about 5, to 8, years ago, and that we are already slowly headed into the next ice age.

The next ice age is predicted to be at its coldest about 23, years from now, Imbrie and Imbriealthough there is a large uncertainty in this prediction. Obviously there are significantly negative effects of human activity on the environment and we do need to clean up our act to ensure the healthiest environment possible for all of us, and future generations, on this planet.

However, it now appears that the contribution of increased concentrations of carbon dioxide and other greenhouse gases in the atmosphere to the observed surface warming has been greatly over-estimated. If our carbon dioxide emissions are not a significant problem, at least as far as global warming is concerned, then a reassessment of our global energy and environmental protection strategies are in order.

Obviously we do need to clean up our exhaust emissions in general, particularly in urban areas, so a move away from gasoline-powered vehicles is desirable. Hopefully we will have the wisdom to focus our finite resources on the environmental problems that we are indeed responsible for and thus can be the most effective at mitigating; global warming does not appear to be one of them.

This wisdom would leave more resources available for the many other problems that plague the human race. InKen joined Morrison Petroleums Ltd.

In early as a result of the take-over of Morrison by Northstar Energy Ltd. In mid, Ken decided to return to university to study global warming and solar variations, a topic that was an incredible blend of his interests in the areas of astronomy, geophysics and environmental issues.

In the fall ofwith the support of his supervisors and the department, his program was upgraded to a Ph. Ken has had articles published by the Recorder and the PEGG, and also presented a poster paper at the GeoCanada Conference, all on the above topic. References and suggested readings:The implications of both past and present climate v ariability and change on agriculture and forestry are the subject of impact studies, some of which ha ve been summarized in the IPCC Third.

Natural climate change in the past proves that climate is sensitive to an energy imbalance. If the planet accumulates heat, global temperatures will go up. Currently, CO2 is imposing an energy imbalance due to the enhanced greenhouse effect.

Past climate change actually provides evidence for our climate's sensitivity to CO2. Past climate change. Historical (past + years): Direct surface weather station measurements of temperature indicate slowly rising global temperatures from late 19th Century until about , then weak cooling until , then sharply rising temperatures up to the present (Fig 2.

Expertise. Insights. Illumination.

Global climate is a result of the complex interactions between the atmosphere, cryosphere (ice), hydrosphere (oceans), lithosphere (land), and biosphere (life), fueled by the nonuniform spatial distribution of incoming solar radiation. Some climate modeling has been done using estimated variations in Total Solar Irradiance, a broadband measurement of incoming solar energy, which indicate that solar variations are a significant contributor to global warming and climate change.

Researchers are looking to the geologic past to make future projections about climate change. Their research focuses on the ancient Tethys Ocean (site of the present-day Mediterranean Sea) and.

For the next two decades warming of about 0. If we continue to emit as many, or more, greenhouse gases, this will cause more warming during the 21st Century than we saw in the 20th Century.
Climate Change: Past, Present, and Future