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Richard Lindzen once again explains. After the hockey stick was global warming sample essay virtually overnight without close examination like the Piltdown Manalong comes Al Gore, a long-time "environmentalist", global warming sample essay, who made near-failing grades in science and math in good college essays who decides to make a movie out of it. The change of CO2 levels between glacial and interglacial periods, of only 7090 ppm, is considered by most authors to be too small to drive the glacial cycle, although Shakun et al. The final signature was from the President of the World Federation of Scientists. Proceed to order Introduction What exactly is global warming and why is it worthy of consideration?



Posted on February 26, by curryja Comments by Javier Summary: Modern Global Warming has been taking place for the past years. It is the last of several multi-century warming periods that have happened during the Neoglacial cooling of the past years. Analysis of Holocene climate cycles shows that the period AD should be a period of warming. The evidence suggests that Modern Global Warming is within Holocene variability, but the cryosphere displays a non-cyclical retreat that appears to have undone thousands of years of Neoglacial ice advance.

The last 70 out of years of Modern Global Warming are characterized by human-caused, extremely unusual, rapidly increasing CO2 levels.

In stark contrast with this rapidly accelerating anthropogenic forcing, global temperature and sea level appear to have continued their rising trend with no perceptible evidence of added acceleration. The evidence supports a higher sensitivity to CO2 in the cryosphere, suggesting a negative feedback by H2O, that prevents CO2 from having the same effect elsewhere.

It is characterized by a preponderance of warming periods over cooling periods, resulting in the warming of the planet, expansion of tropical areas, cryosphere contraction, sea level rise, and a change in dominant weather and precipitation patterns. Afterwards, most of the eighteen century was warmer, but was followed by an intense cold relapse in , before the LIA finally ended around The LIA is the closest the planet has been in 12, years to returning to glacial conditions.

But for the past years, MGW has interrupted the Neoglacial cooling trend of the last five millennia. There is great concern than this and other human actions deforestation, cattle raising, and changes in land use might have an important impact over climate, precipitating an abrupt climate change.

To some authors the abrupt climate change is already taking place. Climate variability over the past years. The time series is made from three segments covered by different amounts of data, which are kept constant within that segment.

Each time series is plotted relative to its mean. Main climatic periods are indicated by background color. Multi-centennial warming periods are indicated by horizontal continuous lines and vertical dotted lines. This series of articles has reviewed how the climate has been changing for the past , years, and with greater detail for the past 12, years.

Climate change is the norm, and climate has never been stable for long. It is within this context of past climate change that MGW must be evaluated. Modern Global Warming is consistent with Holocene climatic cycles It is often said that MGW is unusual because it contradicts a Neoglacial cooling trend that has been ongoing for several millennia. However, this is a superficial observation. Several multi-centennial warming periods have taken place within the Neoglacial cooling trend.

Models simulate global cooling without anthropogenic forcing. However, the proposition that the world should be cooling absent an anthropogenic effect, contradicts our knowledge of Holocene climate cycles. Centennial to millennial solar cycles. The periodicity of this cycle is maintained from Early to Late Holocene, and reflected in the Bond events of increased iceberg activity in the North Atlantic figure Warming and cooling periods of the past years, fitted to known climate cyclic behavior.

The year Eddy cycle is shown in red, with a declining Neoglacial trend of 0. Peak natural warming is expected in AD. There might be an anthropogenic contribution in the MGW, but it is clear that warming at this time is not unusual, and in fact, it is about what should be expected. The most logical conclusion is that natural warming is contributing to the observed warming. If models are not capable of simulating this natural warming, of millennial cyclic origin, then the models must be wrong, and our knowledge of climate change insufficient.

This is a very difficult question to answer. Temperature is an intrinsic intensive property that is changing during the course of a day at any point on the surface of the planet in an unpredictable direction and rate. If there is a global average temperature, we have no way of measuring it.

However, we have devised methods of measuring temperature or radiation at different points on the surface with huge areas unsampled or in the atmosphere. A consistent mathematical treatment of this data gives a consistent value that we term average temperature, although it is not a temperature, but a conversion of intrinsic intensive measurements into an extrinsic extensive value using multiple assumptions.

The change in the global anomaly over the years shows a correlation to real physical and biological phenomena, like length of the growing season, extent of the cryosphere, and sea level rise, among others, and thus it is useful. However, two dangers should be avoided when dealing with the global temperature anomaly.

The first is using the same units for temperature as for the temperature anomaly. The degrees in the temperature anomaly are different than the degrees in temperature, since the connection to physical degrees is lost in the conversion from intrinsic to extrinsic. Many authors are unaware of this problem and attempt to compare proxy derived local temperatures to an instrumental calculated global anomaly.

Also, the precision given in a temperature anomaly is not a precision in measurement, but a precision in calculation. This is also important as the real uncertainty cannot be calculated, due to multiple assumptions in the process that are no properly evaluated.

Due to its low humidity, especially in winter, big changes in Arctic air temperature can take place with small changes in heat content. The weight that Arctic air temperatures should have in a global average is an unresolved question that is biasing instrumental temperature anomalies, relative to temperature proxies.

So, going back to our problem we are now calculating a global temperature with our chosen method, but with no way to relate it to anything similar from the past. The way we estimate climate change from the past is through proxies. The relationship of proxies to temperature is convoluted. Some proxies respond to summer temperature changes, while others to winter or spring temperatures. Other factors, like rate of deposition, rate of upwelling, precipitation, cloud cover, storm frequency, or wind, might affect a proxy often without a clear possibility of correction, as the researcher might be unaware of the bias.

The resolution of proxies cannot match the resolution of our measurements. And proxies are always local in nature. They are two very different things. However, we can answer the question of how unusual MGW is.

Biology offers us a solution. The treeline represents the limit where climatic conditions allow the establishment of new trees. Every year new tree seedlings attempt to establish themselves further up the mountain and generally fail. Holocene treeline changes in the Alps. The approximate Holocene timberline and treeline elevation m above sea level in the Swiss central Alps based on radiocarbon-dated macrofossil and pollen sequences.

Encyclopedia of Paleoclimatology and Ancient Environments pp. We must take into account that present elevated CO2 levels might give current trees an advantage over Early Holocene trees.

The difference in treeline altitude between now and the Early Holocene imply that MGW is not unusual enough to have returned us to Holocene Climatic Optimum conditions. Therefore, present global warming is within Holocene variability. Reasoner and Tinner quantify the summer temperature difference in the Alps between now and the Holocene Optimum as: Arctic sea ice was also very much reduced during the Holocene Climatic Optimum compared to present day, and perhaps ice free less than 1 million km2 during the summers at some periods Jakobsson et al.

MGW is not unusual by Holocene standards in its amplitude, duration, and timing. We cannot rule out that the magnitude of the warming, while not unusual for the Holocene, is unusual for the Neoglacial period that, after all, is characterized by a multi-millennial downward trend in temperatures.

If that is the case however it is very difficult to demonstrate because of the mentioned problems of comparing present and past temperatures.

Circumstantial evidence supports that the RWP was warmer than present Holzhauser et al. Modern Global Warming displays an unusual cryosphere response If MGW is not unusual by Holocene standards, it becomes important to inquire about the climatic response to the increased atmospheric CO2 levels.

Is there anything unusual about MGW? The answer is a clear yes. The cryosphere with the exception of Antarctica is showing a very unusual response to MGW. For the last two decades glaciologists have recognized that global glacier changes over the past years are not cyclical and greatly exceed the range of the previously known periodic variations of glaciers Solomina et al.

And Bakke et al. Contemporary glacier retreat breaks a long-term trend of increased glacier activity that dominated the past several millennia.

The trend of glacier retreat is global, and the rate of this retreat has increased in the past few decades. The observed widespread glacial retreat in the past years requires additional forcing outside the realm of natural changes for their explanation. Modern glacier retreat is not cyclical. The glacier growth index is obtained by adding standardized ELA estimates from southern and northern Norway. Change, 60, , Global glacier retreat is probably the only climate-associated phenomenon that shows a clear acceleration over the past decades.

The World Glacier Monitoring Service, an organization participated by 32 countries, holds a dataset of 42, glacier front variations since , that show that the rates of early 21st-century glacier mass loss are without precedent on a global scale, at least since Zemp et al.

Unusual glacier retreat is confirmed by the loss of small permanent ice patches, also known as glacierets. These permanent ice patches have captured and preserved archeological organic remains during their long existence, and the remains are now being released as they melt. Alpine findings are related to the use of mountain passes when conditions improved, and their dating shows asynchrony with North American findings, associated with summer hunting of caribou, that takes refuge from insects over ice patches.

Thus, Alpine findings are more frequent from warm phases and at the beginning of cold phases, while North American findings are more frequent from cold phases when ice patches became more widespread. Their present climate induced unburial is clear evidence that small permanent ice patches are experiencing a reduction not seen since the Mid-Holocene Transition. Organic remains recently unburied from ice. Source for a -e: The Holocene, 24, 12, They demonstrate the probability that a date from each collection will fall within a particular period and exclude typologically-dated material most of which is Roman in age.

They have been smoothed to a year interval to remove extraneous noise and emphasize more general trends. This reduction is not outside Holocene variability, as multiple studies document a much lower Arctic sea ice extent between and BP Belt et al.

However, an analysis of polar ice shelves thick floating ice platforms , shows an unusual response in present polar ice retreat.



Ten years ago, Al Gore claimed we had 10 years to save the planet from global warming, as pointed out in this Communist BS (CBS News) report from early Unless drastic measures to reduce greenhouse gases are taken within the next 10 years, the world will reach a point of no return, Gore said. by Javier Summary: Modern Global Warming has been taking place for the past years. It is the last of several multi-century warming periods that have happened during the Neoglacial cooling of the past years. Analysis of Holocene climate cycles shows that the period AD should be a period of warming. The evidence.

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