Do you prefer it hot, or do you prefer it cold? Which condition do you think is more conducive to life on this planet? Under which condition do you think Earth experiences greater “biodiversity?”
Do you think that things on Earth, absent mankind’s evil influence, stay pretty much the same or do you think that conditions on Earth are in a constant state of change? If the latter, what drives that change?
Scientists like to categorize things to make it easier to refer to large chunks of time. Let’s take a look at what modern science says about this place we call home. Keep in mind that Science is not an absolute; it is merely the current snapshot of what we think we know about the universe and the world around us.
According to science, the planet we call home has changed radically since it was first formed approximately 4.6 billion years ago. Back then, it was a molten world; hot, barren, with nothing living on its surface. Approximately 4.3 billion years ago the crust solidified and oceans began forming from volcanic out gassing and collisions with water-containing space debris. At this time estimates are that the sun’s output was only about 70% what it is today.
Around 3.5 billion years ago, life arose; at around the 3 billion year mark, this life started producing free oxygen, which gave rise to the atmospheric mix we now enjoy. The period of time from about 2.5 billion to 542 million years ago is called the Proterozoic eon. During this time, which spanned three smaller expanses of time geologists refer to as “eras”, it is thought that the Earth experienced at least two periods known as “snowball Earth”, in which the surface of the planet became entirely or nearly entirely frozen.
The Phenerozoic eon (542 million years ago to the present) followed the Proterozic, and is more interesting as this is where life really began to take off. The Phenerozioc eon is the current eon in the geologic timescale, and comprises the Paleozoic (542-251 million years ago), Mesozoic (250-65.5 million years ago), and Cenozoic (65.5 million years ago to present) eras.
Well now we are down to the last 65 million years. The Cenozoic is divided into three periods, the Paleogene (65.5-23.03 million years ago), Neogene (23.03-2.588 million years ago), and Quaternary (2.588 million years ago to present). Whew! At least we are a bit closer to home! For now, we are just going to look at the Quaternary.
The Quaternary Period includes two geologic epochs; the Pleistocene (2.588 million to 11,700 years ago) and the Holocene (11,700 years ago to present). The Quaternary is distinguished, at least to us, as the time during which recognizable humans existed. Few major new animals seem to have evolved, but there was a major extinction of large mammals in northern areas at the end of the Pleistocene epoch.
The Pleistocene spans the Earth’s most recent period of recent glaciations, while the Holocene is associated with the current warm period, which can be considered as an interglacial period in the current “Ice Age.”
So what is an “Ice Age” and how many have there been in Earth’s history anyway? According to Wikipedia, an Ice Age (or more precisely, a glacial age) is a generic geological period of long-term reduction in the temperature of the Earth’s surface and atmosphere resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers. Within a long-term ice age, individual pulses of extra cold climate are termed “glacial periods” (or alternatively, a “glacial”, or colloquially, an “Ice Age”) and intermittent warm periods are called “interglacials”.
Glaciologically, the term “ice age” implies the presence of extensive ice sheets in the northern and southern hemispheres. We are currently living in an interglacial period during the current ice age. In order for the current ice age, which started the Quaternary Period, to actually be over, it would be necessary for both the Greenland and Antarctic ice sheets to fully melt, something that the current crop of “global warming” alarmists claim would be catastrophic.
There have been at least five major ice ages in the Earth’s past. At times other than these ice ages, Earth seems to have been ice-free even in high latitudes. At present we are still in an ice age, as Greenland and Antarctica are both covered with ice. Since there have been times where we were not in an ice age, i.e., there were no continental or polar ice sheets, and life continued to exist, it is evident that, despite the gloom and doom trumpeted by Al Gore and his ilk, life on Earth has successfully negotiated such “crises” in the past.
So what is all the hullaballoo about global warming now?
First, let’s define a term here. When those on the left refer to “global warming” they are using a form of verbal shorthand. “Global Warming” in their terms means anthropomorphic or human-caused global warming. This is an important difference, and it is to their benefit that the two terms are confused, which is why they have shortened the nomenclature to simply “global warming” in the first place.
As anyone with half a brain already knows, the Earth has been in a warming trend since the beginning of the Holocene, the current interglacial period, 11,700 years ago.
Interglacial periods do not exhibit straight line temperature increases or decreases. Like most natural phenomena, there is a lot of variability. Looking back across the history of an interglacial (and there have been many in Earth’s history), there is a period in each called an interglacial optimum, which is the period within an interglacial where the most ‘favorable’ climate occurs. This is often in the middle of the interglacial, but need not be. The interglacial optimum is denoted by a period where sea levels rise to their highest values and the temperature is at its highest mean values, indicating a ‘better’ climate than the rest of the interglacial.
One would think that we must now be in such an interglacial optimum, since, so we are being told anyway, temperatures and sea levels are higher now “than ever before in Earth’s history”, and are projected to increase until all life as we know it has been wiped from the face of the planet. At least that is what the purveyors of AGW, such as Al Gore, and Prince Charles in England would have us believe. This is the greatest threat the world has ever known, according to them.
And yet, Earth has faced this threat before and survived. Scientists tell us that we have already hit two climactic optimums in the current interglacial; the Subboreal (3000-500 BC) and the Atlantic (7000-3000 BC). In both of these, mean sea levels and mean planetary temperatures were higher than today. In the Atlantic period, for example, sea levels rose to 3 meters higher than recorded today. And yet, the Earth, and life on the Earth (including we humans) survived.
Ours is not the first interglacial period to occur during the current “Ice Age” we are experiencing. In the interglacial immediately preceding ours, the Eemian, sea levels as much as 8 meters (~26 feet) higher than today and the water temperature of the North Sea was about 2 degrees Celsius (3.6 degrees Fahrenheit) higher than at present. Somehow, life muddled through.
Overall, the climate was much the same although at the climactic optimum, forests reached areas in Norway well above the Arctic Circle in areas that are now tundra and hardwood trees grew as far north as Oulu, Finland. In the northern hemisphere, winters were somewhat warmer and wetter than they are now, and hippopotamus were found as far north as the Rhine River in Germany and the Thames in England.
So what, if not human mischief, causes these periods of variability and instability in Earth’s climate? There were no humans around during the Eemian to cause global warming.
There are many things that conspire to cause climate change in the world in which we live. Many things which we assume to be constant, in reality are not. The earth’s orbit around the sun is not as “fixed” as most people think. Variability in eccentricity, axial tilt, and precession, resulting in cycles known as Milankovitch cycles, are thought by some to contribute to the long-term climactic variation. Certainly they do have some effect on our climate.
For example, the axial tilt of the earth varies over roughly a 41,000 year period from 22.1 degrees to 24.5 degrees. Axial tilt is the angle between the axis the earth rotates around and the plane of the earth’s orbit around the sun. It is this axial tilt that is responsible for the seasons (spring, summer, fall, and winter) we experience. As the tilt increases, summers in both hemispheres are longer and winters shorter; as the tilt decreases, the opposite occurs. Currently, earth is inclined at 23.44 degrees with respect to her orbital plane, pretty much in the middle. The tilt is currently decreasing and will reach its minimum around 10,000 AD.
The sun also, is not static with regard to solar output. Most of us are familiar with the 11-year sunspot cycle. Total solar output from start to finish, over the last three cycles has been measured by satellites. The difference is only about 0.1%. We have no direct means to measure long term variation in solar output, however it is thought that it has remained relatively constant for at least the last 2000 years. It is also thought that way back when the earth was first formed, solar output was only about 70% of what it is today. Obviously it has varied over the life of the planet. However solar variation today, in and of itself, is considered too weak to explain current climate change.
But then again, perhaps there are other mechanisms at work other than just raw solar output to explain climate change. Or perhaps that small variation is enough to drive an even larger mechanism, much the way a lever and a fulcrum magnify one’s ability to lift large weights.
A recent theory by Henrik Svensmark, a Danish physicist postulates solar activity as an indirect cause of global warming. According to Svensmark, cosmic rays are involved in cloud formation here on earth. The more cosmic rays we have arriving from outer space, the more clouds we have. The more clouds we have, the cooler the planet gets, as more of the sun’s radiation is reflected by the cloud layer. The amount of cosmic rays we receive on earth is related to the intensity of the solar wind; as the solar wind increases, incoming particles are decelerated and some are blocked, resulting in fewer cosmic rays and, according to the theory, less cloud formation resulting in planetary warming.
This begs the questions, can cosmic rays affect cloud formation, and has the solar wind increased recently, blocking cosmic rays, resulting in fewer clouds and thus more warming?
Recent experimentation at CERN has shown a possible link between cosmic rays and cloud formation. The experiment used a sample atmosphere which simulated the earth’s upper atmosphere and bombarded the sample with cosmic rays. The results? Cloud nuclei were produced. Cosmic rays can cause clouds. Does this mean that all clouds are caused by cosmic rays? No. But it does mean that they are linked to the formation of at least some clouds. More rays, more cloud formation; less rays, less cloud formation. Thus, indirectly, cosmic rays may affect the climate.
So what about the sun? Is the solar wind increasing or decreasing? Data collected from space shows that the dynamic pressure of the solar wind hit a relative maximum in 1991 and has been falling steadily since.
Has the solar wind fallen off? It appears so. Anyone who has been following solar “weather” recently is no doubt aware that there has been a dearth of sunspots over the past few years. In fact, there have been long periods where there have been no sunspots at all. A lack of sunspots appears to be an indicator of less solar activity (although the sun can send some mean “weather” our way, even in the relative absence of sunspots). Less solar activity means more cosmic rays and more cosmic rays means more cloud formation and cooler temperatures on planet Earth.
Keep in mind that this is a theory. There are many who still dispute that cosmic rays have an effect on cloud formation on Earth, and that even if they do, it isn’t enough to really affect our weather. Perhaps. But it is interesting to note that the recent decline in solar activity coincides with lower global temperatures over the past decade or so.
It is also interesting to note that the coldest part of what is known as the “Little Ice Age” (~1550 AD to 1850 AD) coincides with a period know as the “Maunder Minimum”, an extended period of minimal sunspot activity lasting from ~1645 AD to 1715 AD. Previous sunspot minimums (Dalton Minimum and Sporer Minimum) also coincide with periods of lower-than-average global temperatures. We have been in an extended sunspot minimum for six years now, and there are predictions that the next sunspot cycle, cycle 25, will be greatly reduced or may not happen at all.
This has caused some to speculate that we may be entering one of those extended solar minimums like the Dalton, Sporer, or Maunder. According to scientific evidence, our sun spends up to a quarter of its time in sunspot minimum, and we haven’t had one since the end of the Maunder. If so, based on past history, we can expect longer and deeper winters than we have experienced in recent history. Winter weather patterns of the past several years seem to be headed in this direction.
This means that within our lifetime, we may be able to experience both global warming and global cooling, and decide for ourselves which we prefer. It should be noted that with colder temperatures come shorter growing seasons. This means that crops that we currently grow may only be viable at lower latitudes than present. This translates into, among other things, less food to feed the now-estimated 7 billion people inhabiting our globe. It also translates into a greater need for energy resources to keep warm during the longer, colder winters.
It also means that no matter how much we tax and spend, there may be little if anything we can do to “fix” this. How much money do you think we would need to spend to cause the sun to start generating sunspots?