The media, politicians, and environmentalists have convincingly sold the idea of Global Warming to the masses. Their continued focus on calling weather related events as effects of mans misuse of the earth has persuaded many that it must be true, and it must be because, almost everyone is claiming it's true. Unfortunately, this is all the further most will go to seek out the facts.
The unscrupulous has learned how to program the populous to follow their agendas by simple repetition. It helps when this repetition comes from different media sources, as it tends to lend credibility to the claims. They tend to focus on the studies supporting their claim, while downplaying the critics. When they are wrong, no one hears about it.
The American Heritage Dictionary of Science defines global warming as "an increase in the average temperature of Earth's atmosphere," either by "human industry and agriculture" or by natural causes like the Earth has "experienced numerous" times "through its history."
The current period of global warming is similar to many that have occurred in the past, some of which were cooler or warmer. There have been many rapid climate changes, warming and cooling, in the last few million years, many on time scales of decades or less. Obviously, man had nothing to do with them, but what about the time since the Industrial Revolution?
Disasters like Hurricane Katrina are not indicative of global warming doomsday. The Nile River (829 AD) and the Black Sea (800-801 AD) have both frozen. At one point, glaciers were within five degrees of the Equator. A glacier formerly existed on Hawaii, and glaciers once covered almost all of Canada, New England, and the northern central United States.
The average global sea level has been generally rising since 1860 or earlier, which is about 45 years before surface temperatures began to rise and 75 years before man-made emissions of CO2 reached 1% of natural emissions. Moreover, sea levels are often dropping and rising at the same time at different places on the planet.
Some of the theorized causes of past climate change includes ocean circulation, changes in atmospheric concentrations of greenhouse gases or haze particles, soil moisture, and changes in snow and ice cover. Haze particles, snow and ice cover hinder the amount of solar radiation reaching the earth. Greenhouse gases trap the heat in the lower atmosphere. Another factor is cyclical variation in Earth's orbit around the Sun. The basic idea is that these cycles cause variations for radiation the Earth receives. Clouds are yet another factor, but they can both cool and warm, depending on its characteristics. There are many factors, each affecting climate in a variety of ways, all at the same time. Scientists have only a limited view of this coordinated process showing the study of global warming is still in its early stages. To say that we are at a tipping point, based on today’s weather, is at best speculative.
CO2 accounts for 12% of the greenhouse effect, while water vapor and clouds comprise 36% and 14%, respectively. The ozone and methane have a 3% and unknown portion, respectively. Of the 12% of CO2, human activity accounts for 26%. In all, man is responsible for 3.12% of the total greenhouse effect. The rest of the CO2 (74%) is natural and recurring. The scientific community is not even sure how much methane is in the atmosphere. In fact, they are not even sure how much CO2 the earth holds.
Water vapor is a more important greenhouse gas than carbon dioxide, and as its atmospheric concentration can vary rapidly. It could have been a major trigger or amplifier in many sudden climate changes. Large, rapid changes in vegetation cover might also have added to these changes in water vapor flow to the atmosphere.
Since the outset of the industrial revolution in the late 1700s, the carbon dioxide concentration in Earth's atmosphere has increased by about 34%, most rapidly from about 1960 onward. As we do not have decade-by-decade information on CO2 concentration throughout history, we have no way of knowing how rapidly CO2 accumulated during warming periods.
Rapid changes in temperatures have occurred throughout history. For example, the end of the Little Ice Age (~1650 AD) probably occurred in just a few decades. The tendency of climate to change relatively suddenly has been one of the most surprising outcomes of the study of earth history, specifically the last 150,000 years (e.g., Taylor et al., 1993).
The current temperature increase is unspectacular, as climatologists believe that during most of Earth's history, global temperatures were probably eight to 15 degrees Celsius warmer than they are today.
The irony of global warming claims is that little is said of the areas that add ice while it reduces in another or that some areas warm as some cool. We also do not hear of how the earth responds to both cooling and warming to offset the changes. As of 2009, atmospheric CO2 concentration is about 387 parts per million (ppm). By increasing the CO2 level in the greenhouse atmosphere (typical to 600 ppm instead of normal 400 ppm value), the growth for some plants can be stimulated in an important way, with often yield increases up to 20%, especially for tomato, cucumber, strawberry, etc.
A December 2011 article in the journal Paleoceanography reported paleoclimatic records suggest CO2 concentrations (at least in the Northern Hemisphere) may have been around 400 ppm between 2 and 4.6 million years ago. These CO2 estimates gradually declined from just above 400 ppm to around 300 ppm in the early Pleistocene 2 million years ago.
So even as global warming proponents claim we are at the tipping point, remember the earth has been here before. Yes, CO2 concentrations are higher and appear man-made over the short term, but over the long period, the spike is less convincing. The earth, throughout history, has repeatedly responded to warming periods with periods of cooling, so why would we expect something different this time.