WHAT ARE THE POSSIBLE CAUSES OF CLIMATE CHANGE

 

WHAT IN THE Devil is going on? They are calling it climate change, but isn’t a changing climate a constant thing?

 

Global warming is obviously what we are concerned about, but global warming is not a constant thing. Sometimes there is global cooling, often to the extreme, as is evidenced by past ice ages. There is even evidence of a snowball earth once or twice in the past when practically the entire globe was frozen over. There are indications that this was the case about 635 million years ago.

 

Below is a graphic compiled by the blog “Skeptical Science.” Don’t let the name fool you, they are anything but skeptical about anthropological global warming and the effect of human-generated CO2.

It shows the conclusions reached by a number of different studies as to contributions to global warming.

 

It does not include any margins for error and I cannot guarantee that studies were not cherry-picked to agree generally with the beliefs of Skeptical Science. I also cannot guarantee that the data used for the studies were not biased or chosen as more likely to reach a given result.

 

 

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Notice that even the most conservative puts 100% of the blame on greenhouse gases. How do you get more than 100%? Well, apparently the conclusion was that there would have been considerable cooling without GHGs. I am fairly certain they meant human-emitted GHGs since without a certain level of greenhouse gases in our atmosphere the earth would almost certainly be a frozen ball.

 

The most conservative also blames human activity for 50% of global warming. Well, I may be able to swallow that.

 

This is another climate analysis that differs. It is rather long but has excellent graphics. Everyone interested in climate science should read it.

 

We do need to understand what greenhouse gases are. This link to a post in a blog by the GHG management institute describes GHGs, and this one explaining GWP, or global warming potential, is good to study.

 

 

 

What is pretty obvious, is that a CO2 increase in the atmosphere from the burning of fossil fuel has been singled out as the primary villain. How is atmospheric CO2 level determined? Check the links for more information. What is carbon dioxide?

 

Humans have clearly altered the path of the climate of the earth. Scientifically one never claims 100% certainty. However, one can say the conclusions are unequivocal. This essentially means that there are no other theories that can invalidate the conclusion.is a quote I came across at some point. Well, I can’t disprove the existence of a supreme being or multiples of such entities, either. The statement indicates that many have made up their minds, are no longer looking for any other explanations and in many cases will not even consider other contributing factors.

 

There are different viewpoints. Dr. Roy Spencer is one scientist that I consider very credible and one who is willing to change his opinion as new evidence arrives.

 

Tony Heller is another credible scientist with a rather more skeptical view of global warming. His blog.

 

Contributing factors, both natural and anthropogenic, include other greenhouse gases, solar insolationalbedo changes, or simply inaccurate data. Other factors affect climate, but some, like volcanoes with dust blocking sunlight or by adding carbon dioxide, have contradictory effects.

 

Water vapor is the most abundant and probably the most powerful GHG, but it is seldom mentioned. It is short lived (quickly falling out of the atmosphere as precipitation), is not evenly distributed and the effects of the albedo of cloud tops is poorly understood. Most would notice that cloudy nights are warmer but cloudy days are cooler. This makes water vapor very difficult to quantify as a contributor to climate change.

 

Water vapor in the atmosphere should increase as the earth warms since warmer air can contain more moisture, there is more evaporation from warmer water, more transpiration from plants, and more surface area of water bodies.

 

Does this lead to a net warming or a net cooling?

 

 

Carbon dioxide is probably the next most abundant GHG, but it is far from being the most powerful. 

 

Methane has at least 10% of GHG effect in spite of being much less abundant in the atmosphereWhat is methane?

 

CO2 quantities are much more easily measured in spite of comprising only about 0.04% of the atmosphere. This is because it is relatively evenly distributed, due to a long life in the atmosphere. However, both CO2 and methane concentrations, like water vapor, increase with increasing temperatures. Confirmation for this was seen when CO2 spiked during El Nino. So although there is a definite correlation between CO2 concentrations and temperature, which came first, the chicken or the egg.

 

In no way am I suggesting that  COlevels are not influenced by emissions from human activity. We may have increased CO2 by as much as 120 ppm (0.012%) in the last 150 years or so, assuming that CO2 levels were in a balanced and steady state prior to this. There is also no doubt that  CO2 can have a warming influence, although several scientists argue that it is limited.

 

This site by Clive Best may help you understand some things about the effects of CO2.

 

I am not qualified to comment what CO2 can or cannot do, I am just not certain that it has been proven the major cause of the temperature increase of about 0.85 degrees centigrade since about 1880.

 

  

 

 

By Reg Morrison, CC BY 2.5 au, https://commons.wikimedia.org /w/index.php?curid=34937508

 

 

Be a little careful with the above graphic. Carbon dioxide measurements are in parts per million while methane is in parts per billion.

 

When discussing the contribution of solar isolation let’s go back to past glaciations for a moment. Most scientists agree that glaciations began as a result of a decrease in solar insolation (a possible result of the earth orbit, axis tilt, and solar variance.) Why then is an increase in solar isolation not sufficient to end an ice age?

 

Why would an increase in CO2 be necessary? Where would the extra CO2 come from? Certainly not biotics in a much cooler environment? That really only leaves volcanic action, but is it possible that volcanic activity ebbs and flows on as regular a period as glaciations appear to have. Is it possible that carbon dioxide levels increased as a result of higher temperatures and the retreat of the ice? It is possible that the oceans could release CO2 as a result of decreased pressure (as a result of much lower sea levels.) This does not seem very likely, however, in a snowball earth scenario where almost the entire globe may have been frozen over. 

 

The other big question is, why did the earth descend into ice ages in spite of relatively high levels of carbon dioxide in the atmosphere.

 

 

 

Unless you live in an area that has snow cover for much of the year you may have a tendency to dismiss the importance of the planets albedo and the impact of human activity on it. A clue may lie in the observation that it is the northern hemisphere seems to be most affected by warming. This, of course, is where the largest land mass lies and where the largest portion of the cryosphere exists.

 

Everyone in the north has likely noticed the large effect that even a footprint has on snow when the sun falls upon it during warmer days. Even more striking is the effect of dust or soot on the surface of snow or ice. Most have probably also noticed the substantial melt back along cleared roadways as days warm. In this manner, human-kind has a tremendous impact on the cryosphere.

 

I have been known to joke, that scientists, concerned with the melting of glaciers, should quit leaving their footprints all over them.

 

Cultivation of land for agriculture also affects albedo. Even asphalt paved roads in the desert increases the absorption of heat during the day which is released back into the atmosphere. Quantifying this effect would be difficult but, have any scientists even tried.

 

And then there is the difficult to quantify, albedo changes from the ebb and flow of cloud cover. Remember those white fluffy cloud tops visible from your airliner window.

 

Finally, How accurate is our data? Keeping records is a fairly recent endeavor and started with relatively few reference points (land-based instruments.) Even if the instruments were extremely accurate, and all calibrated to the same standard, even a slight bias by the observer recording the readings or a slight difference in the time of day that a reading was taken could result in significant error when dealing with such a small temperature difference over such a long period of time. Granted, errors could be in either direction.

 

In more recent years we have had access to presumably much more accurate satellite instrumentation, but the time span has hardly been sufficient for concrete conclusions.

 

Earlier than 150 or so years ago nearly all the data relies on proxy evidence, which has to rely on confirmation from several different proxy sources, and is likely not very accurate when it comes to smaller differences.

 

One of the major variables is the wide discrepancies between the number of observations from one area of the globe to another. For example, Antarctica has had fewer than a dozen observation points on a continental area nearly twice the size of Australia.

 

After a recent hiatus in significant climate warming that lasted about 15 years (in defiance of IPCC modeling,) scientists searched desperately for the hidden warmth and decided that it was in the oceans of the world. The problem with this is that there has been a severe lack of ocean temperature observations. The oceans are at least as dynamic as the atmosphere, and in order to know if there was an increase, you would require a very high number of measurements over a relatively long period. Running around the seas for a few months, pulling up buckets to sample, just isn’t going to cut it.

 

I believe that the best our data can do is identify trends. However, the trend seems to be towards a warming climate. That is hardly enough information for making long-term predictions. For that, all we have is modeling which can only give us probabilities at best and so far have only been proven to be moderately accurate when run backward. So what does the future hold?

 

The only way to be certain is to wait and see.