Global Warming: Is mankind guilty?
There is no question that the earth’s overall climate goes through various cycles. At this time, there is something of a consensus among scientists that warming is taking place. There is a lesser consensus that mankind is causing it, although man’s activities may accelerate it.
The recent history of climate in North America shows overall warming in the past 13,000 years, but cold spells have occurred as well. At 13,000 years BP, the ice sheets which had covered North America were rapidly receding.
However, around 12,800 BP, a new cold spell known as the Younger Dryas took over, and dropped the northern hemisphere’s temperature sharply until the period ended around 11,500 BP. It may have affected the southern hemisphere as well. During that time, glaciers advanced again, and there appear to have been severe effects on the flora and fauna in what is now the US and Canada. It is also believed that the North American peoples of that time were also severely affected. No Clovis stone tools have been dated after Younger Dryas.
The Earth’s temperature has warmed and cooled, over cycles of hundreds of years, consistently. In the past 4500 years there have been at least 75 major temperature swings, according to Harris-Mann at http://www.longrangeweather.com/global_temperatures.htm
Whenever solar radiation has decreased and volcanic activity has increased, global temperatures have plummeted, often within months. The climate has never remained “normal” during the past 4500 years; instead, it has manifested itself as warm periods interspersed with cold periods. Most of these periods lasted hundreds of years:
2500+ to ~1900 BC – a warm period
~1900 to ~1500 BC – cold spell
~1500 to 560 BC – a very warm period
~560 to ~0 BC – cold spell during the time of the Greek Empire
~ 0 to ~535 AD – warm spell during much of the Roman Empire
~ 535 to ~900 AD – cold spell during the Dark Ages
~900 to ~1350 AD – the Medieval warm spell
~1350 to ~ 1885 AD – The Little Ice Age, very cold
~1885 to ~1990 AD – Warm spell covering most of the 20th Century
~1991 to ~1998 AD – A brief cold spell, seemingly caused by Mount Pinatubo
~1998 to ~2006 AD – Warm spell, again (essentially a continuation of the interruption)
~2006 to present – A brief cold spell (possibly ended)
The graph at the Harris-Mann website referenced seems to indicate we are coming out of a very short cold period at the present time, and sharply peaking into a new warm, dry period. It plots the estimated global average temperature, and shows a high of around 60° F and a low of around 54, around a norm of 57. The website contains the following text, although the description of what typically happens in the periods named has a very small sample basis and may not be predictive in any way.
There were four distinct type of patterns that were noted since 600 B.C., ‘warm-wet’, ‘warm-dry’, ‘cold-wet’ and ‘cold-dry’ cycles. Also, about every 500 years, our planet also goes through a cycle of Wide Weather ‘Extremes’. Our current cycle of extremes has been the worst in 1,000 years, since the days of Leif Ericcson, the mighty Viking explorer.
A ‘Warm-Wet’ cycle is the best cycle for global prosperity and strong leadership. During this period, global temperatures are warmer and global precipitation will be a little higher than normal. Since the 1980′s, global temperatures are over a degree warmer, which has fueled the debate over ‘global warming’. However, people’s moods are usually better in warmer and wetter times which tends to ‘bullishly’ affect the stock and commodity markets. During the 1990s and early 2000s, there was tremendous economic growth across the world. With the exception of the Iraq war, much of the planet enjoyed relatively peaceful times.
A ‘Cold-Wet’ cycle does have some growth, but migrations do increase as temperatures are generally cooler than normal. However, with more moisture, many counties still thrive, but again, the ‘warm-wet’ cycle is the best one for growth and prosperity. However, as the saying goes, “sooner or later, all good things must come to an end.” Well, the bad news is that we’re looking for the worst climatological cycle, or a ‘Warm-Dry’ phase to occur. And, as we transition from the ‘Warm-Wet’ phase towards the ‘Warm-Dry’ one, we may see ‘extremes’ that will make this current cycle of ‘extremes’ look like a walk in the park.
A ‘Warm-Dry’ cycle typically means that temperatures on a global level are a little warmer, but precipitation is noticeably less than average. During this time, there are massive worldwide droughts and crops are severely strained. Studies have indicated that when we have experienced warmer and drier conditions, you often see a period of ‘bad times.’ As a result, there are usually ‘bad’ leaders, as was the case in World War II when Hitler and Mussolini dominated the European continent.
Our last major ‘Warm-Dry’ phase occurred during the 1930′s. Of course, many do remember the infamous ‘Dust Bowl’ and worldwide drought and depression. This pattern completes a 102-year cycle which dates from 1936. And, if history is any indication of what’s to come, our chart says that we could see a huge stock market crash, global depression, new outbreaks of unknown disease, and perhaps, a third World War if we stay warm and precipitation levels fall on a global scale sometime between 2020 to 2038.
‘Cool-Dry’ phases are also bad, not as severe as the ‘Warm-Dry’. Precipitation is still below average during this cycle, but temperatures are cooler than normal. During the 1980′s, we went through a period of cooler and drier than normal weather. During that time, the stock market hit its lowest level since the Crash of 1929. There was three severe droughts in the Corn Belt during the 1980s, 1980, 1983 and 1988. Plus, we had volcanic eruptions that particular decade and widespread political unrest. Many people who we’ve talked to have said that they would like to “forget the 1980′s weatherwise and otherwise.”
The editorial observations in the quoted text above aren’t scientifically sound, and should probably be disregarded.
A very good blog that debunks man-made global warming can be found at Roy Spencer’s blog. Spencer, a climate scientist, has unimpeachable credentials.
Another interesting site is Climate Skeptic, where considerable information by Warren Meyer can be found that totally debunks catastrophic man-made global warming. Unfortunately, the current site has a faint text that is difficult to read. Several of mankind’s modern activities are considered as likely to amplify the projected future warm-dry spell. They include:
- emission of carbon dioxide gas into the atmosphere, primarily through the use of fossil fuels;
- deforestation of large areas of the earth, including the Amazon basin, portions of India, and many huge Pacific islands such as New Guinea and New Britain;
- The vast concrete, metal and stone expanses of man’s cities, which absorb and re-emit heat.
- The exhaust of many millions of automobiles and trucks, constantly moving over the world’s highways.
Other factors which act to retard the warming include:
- volcanic activity, which inserts dust into the atmosphere.
- the jet contrails in the upper atmosphere
The sun’s energy penetrates Earth’s atmosphere and brings heat there and to the surface. Energy is radiated back into space on multiple frequencies. The incoming heat and the outgoing heat must be in balance, or the Earth’s climate will adjust to bring it into balance.
Proponents of the idea that increasing CO2 will cause a global warming catastrophe expect positive feedback to occur that will amplify the temperature increase. This feedback is expected to be caused by:
- Increase in atmospheric H20 content due to increasing temperature, and water vapor has a stronger greenhouse effect than carbon dioxide;
- Increase in methane content of the atmosphere, due to melting of Arctic tundra, methane is also a strong greenhouse gas;
- Increase in high cirrus clouds due to higher relative humidity; (this actually may be a negative, due to increased reflection);
- Increasing release of CO2 from warmer oceans;
- Decrease in Earth’s albedo (heat reflection) due to disappearance of snow and ice cover.
Scientist advocates of coming catastrophic global warming predict high percentages of positive feedback, so as to assume a warming of up to 10° F over the next 10-20 years. Yet, the Earth’s climate has historically behaved as a negative feedback system. Predicted temperature curves do not project back into the past, which should have shown much sharper rates of increase if the feedback had been positive and caused the same effects as are predicted for the future. All historical climate evidence indicate that weather responds to negative feedback effects, and thus remains rather stable over long periods.
Global warming has become a political issue, and its claimed catastrophic future is strongly supported by the left. However, since there has been no measurable warming since 1998, it has been rebranded for publicity purposes as “Climate Change.” This allows its advocates to claim that occasional years of excess hurricanes and tornadoes are due to man-made effects. There has been no upward trends in hurricanes, although more tornadoes are recorded due to better reporting and radar technology.
In actuality, CO2 can only affect world climate by raising Earth’s land and sea temperatures.
Climate change and global warming are not synonymous.
The US Environmental Protection Agency has a website devoted to climate change, EPA Climate Change website which seems to take the catastrophic view of the future. There is a page devoted to future temperatures, which predicts an increase of 2 to 11.5 degrees by the end of the 21stcentury. While the EPA discusses feedback, they assert it is almost certainly positive.
Remember, there is a consensus among many scientists that catastrophic warming will occur. Politicians also accept the theory. The EPA is merely following the consensus.