What is global warming, anyway?
It is the warming of the lower atmosphere over the entire Earth, averaged over a long period – at least a few decades. The Earth always warms in some areas and cools in others, even when no global warming or cooling is occurring. Thus it is important to realize that to say that global warming is occurring, it must be a warming of the entire Earth.
What are the causes of global warming or global cooling?
There are many factors that can cause the Earth to warm or cool, and it has done so throughout its history. From the amount of radiation given off by the Sun (which can vary) to volcanoes, to cloud cover, to eccentricities in Earth's rotation and orbit, many factors contribute to the Earth's temperature.
There are gasses called greenhouse gasses because they keep some of the Sun's energy from leaving the Earth. These can cause global warming. The main greenhouse gas is water vapor (the invisible water in the Earth's atmosphere). It has been estimated that without water vapor and clouds in our atmosphere, the Earth's temperature would be 60 to 80 degrees Fahrenheit cooler than it is now. (All temperatures given here are in degrees Fahrenheit). Carbon dioxide, methane, and some other gasses also cause global warming. The greenhouse gas that humans emit when burning fossil fuels that has the most significant effect on global warming is carbon dioxide.
What is anthropogenic (man-made) global warming (AGW)?
This refers to the amount of global warming that is the result of human activities. Since the mid part of the 20th century, humans have burned fossil fuels for energy, and this has increased steadily. It is now especially increasing due to the emergence of developing countries, and developing countries are expected to contribute most of the future increase in atmospheric carbon dioxide. For instance, since 2006, China has been the main contributor of CO2, and China is building about one coal-burning plant per week! Aside from the burning of fossil fuels for energy, the cutting down of trees in the Amazon has been cited as a major reason for increased CO2 in the atmosphere, because all green plants and trees take in CO2 to "breathe." They convert CO2, water and sunlight into carbohydrates and oxygen, a process we know as photosynthesis. Animals then eat these plants because they can digest carbohydrates, and along with the oxygen they breathe, produce energy for their bodies, and then breathing out carbon dioxide. This is the oxygen cycle that we read about in school.
Another major contribution humans make to additional CO2 in the atmosphere is the result of out-of-control coal fires. Not infrequently, when we attempt to mine coal, it catches fire. Developing countries frequently do not have the ability to put them out, and coal fires are very hard to put out. It has been estimated that in China alone, coal fires give off about the same amount of CO2 as the U.S. does from our burning of fossil fuels.
What evidence do we have the humans are a cause of at least some global warming?
At the rate we are adding CO2 to the atmosphere, it is expected that the CO2 concentration will double from 325 parts-per-million (ppm) to 650 ppm by around 2060, mostly as a result of human burning of fossil fuels. Because CO2 is a greenhouse gas, this gives us reason to suspect that humans are contributing to global warming.
How much global warming has occurred until now?
During the 20th century, it's estimated that the Earth's average temperature increased 1 to 1.5 degrees, and that sea level rose about a foot. Satellite measurements of temperature for the 30 year period from 1979 to 2009 show that the Earth warmed about an average of 1 degree over that period.
How much global warming and sea-level rise does the evidence suggest will occur during the 21st century?
Extrapolating upon the warming trends given above, the Earth would warm from 2 to 4 degrees during the 21st century. A number of climatologists think that an increase of 3 degrees in global temperature will have a net positive effect on humanity, although there will be some negative effects in some areas. So if current trends continue, global warming is not likely to cause significant harm. For instance, if the Earth were to warm an average of 3 degrees, the U.S. Midwest, and Canada would have a longer growing seasons, as would Russia. This would contribute to the world food supply. Sea level is rising at a rate that would indicate a 1 to 2 foot increase during the 21st century. This is also not likely to cause significant harm.
If this is true, why is there so much concern over global warming?
As is well known, the media tends to fixate upon news that exaggerates the negative, and tend to report on stories that are alarmist, and ignore stories that are not. So, the scientific studies that show that global warming may not be a disaster tend to be under-reported. Have you noticed that the term, "climate change", has replaced "global warming" in many articles? Part of the reason for this is that the Earth has not warmed from 1997 to 2013, and this may go on longer. This is not to say that global warming will not occur – I believe that the evidence shows that it is occurring, just not at a rate that is cause for alarm.
What do climate models predict about global warming?
Climatologists have come up with many climate models in an attempt to predict how much global warming will occur. Most of these models predict temperatures will increase anywhere from 1 to 11 degrees during the 21st century, according to the United Nations' International Panel on Climate Change (IPCC) final report. This is an enormous range of uncertainty, but such uncertainty is called for since these climate models have not been verified. Also, climate is a non-linear system, and is determined by many factors; climatologists are not certain how these factors interact. It may be that, like weather, we may be unable to predict climate decades into the future. (Due to the mathematically chaotic factors that produce our weather, it is impossible to predict it more than 10 or so days in advance. And that's not going to change with faster computers or more knowledge, because of the nature of scientifically chaotic systems. This may be the case with climate as well).
Could the Earth actually warm near the top end of the predictions?
Yes, it is possible. First, we know little about how to predict climate. Second, we know from past evidence that climate can change quickly, so an increase of 9 to 11 degrees over the next century cannot be ruled out.
What is the best way to mitigate the negative effects on humans if significant global warming does occur?
Cost-effective ways to reduce or even stop global warming will be given below. But it is very important to understand that if global warming occurs to a significant extent, then, just as when other disasters happen, the most prosperous countries fare much better than the poorest countries.
The lesson of the 2010 disastrous earthquake in Haiti was that it wasn't the earthquake that killed hundreds of thousands of innocent people, it was poverty. Haiti did not have buildings or roads or the various types of infrastructure able to handle a 7.0 magnitude earthquake. In 1989, San Francisco had an almost identical earthquake, and around 60 people were killed.
Prosperity matters a great deal, when it comes to dealing with any kind of disaster. Prosperous countries will be in the best position to deal with whatever negative effects there might be due to global warming. Not only will these countries suffer less if significant global warming occurs, they will suffer less if any disaster occurs. In addition, prosperous countries rarely go to war with each other. It is easier just to trade with each other than to go to war.
What are the best ways to make a country prosperous? The answer to that is beyond the scope of this monograph, but I've given a number of answers in my Political Platform Based Upon Natural Law series. The one-sentence answer is that the most prosperous countries are those that are closest to being free-market, constitutional democracies.
So what are some cost-effective ways that will stop any significant global warming this century?
There are a number of inexpensive solutions to global warming that will work even if warming is not man-made. I'll give two of the more promising ones. For more solutions or more details about the solutions I'll give below, get Steward Brand's Whole Earth Discipline. He is the author of The Whole Earth Catalog, one of the seminal environmental books of the 20th century.
The first choice of most climatologists involves employing stratospheric sulfates. The reason this is the first choice is that it is already known to work. In 1991, in the Philippines, Mount Pinatubo erupted, sending millions of tons of sulfur dioxide twenty miles up into the stratosphere. This soon created tiny sulfate droplets that absorbed and reflected sunlight. The next year, the entire planet cooled by about 1 degree!
After a 1998 presentation by Lowell Wood at a climate conference about this, climate modeler Ken Caldeira created some models to determine if a stratospheric-sulfate scheme would work, and the models suggested that it could work very well. His models indicated that if we would inject 10 gallons of sulfates per second into the stratosphere, we would be protected from global warming for the entire century. This is a relatively small amount since we are putting 100 million tons of sulfur dioxide per year into the atmosphere right now, and should have little or no negative side effects. And if we find after a while that it's not needed, we can stop and within a few years, things will be back to normal.
And what is the cost of this scheme? Estimates are around $30 billion dollars per year – almost an insignificant amount. By comparison, the U.S. federal government's budget was about $3.5 trillion in 2009, which is the same as 3,500 billion dollars, in a single year.
How can we be sure that the model's predictions are correct? We could inject a small amount of sulfur into the stratosphere in the Arctic, where warming is occurring now. Then we could measure the impact. If it works, we can ramp up the experiment until we're convinced that it is a viable solution.
One other solution to near-term global warming involves the idea of having a fleet of oceangoing cloud machines. There would be an estimated 1,500 unmanned ships that would spray sea-water droplets up into the clouds at a rate of 500 gallons per minute. This increase in cloud volume would be enough to reflect sufficient sunlight away from the Earth to offset a doubling of CO2 in the atmosphere. The cost to build the ships: around $3 billion dollars. And the amount of the spray could be easily adjusted to accommodate however much warming is actually occurring.
The above geo-engineering solutions don't reduce global warming gasses, even though they will reduce or stop global warming. What are some cost-effective ways that will stop global warming in the long run?
In my previous post I gave an environmental policy for the United States that will reduce pollution and CO2 emissions by at least 90% by 2060. And the surprising news about this is that it will create prosperity at the same time. This is about the most anyone could ask for.
The bad news is that the U.S. is unlikely to adopt these policies quickly enough, even though the policies are quite practical. The main part of the policy is to build natural gas power plants for the next 20 years or so, and then build nuclear power plants whenever we need more energy.
The better news is that nuclear power is growing very quickly world-wide. There are about 30 countries that are currently using nuclear power, and over 50 are planning on using it. Because of modern reactor design and the prevalence of uranium and thorium, as well as the development of cost-effective solar energy, it is likely that by the end of the century, very little pollution or human-caused CO2 will be given off.
The upshot of this is that by the next century there will be little or no greenhouse gasses given off.
The current evidence shows the Earth will warm about 3 degrees this century. If that turns out to be the case, it will likely be a net benefit to humanity. If we then follow the environmental policies that I've given in a previous post, humans will be contributing very little to whatever global warming may occur next century, and we will prosper at the same time.
And if global warming occurs at a rate that would lead to more than a 3 degree increase this century, there are a number of very inexpensive ways to deal with it, as I've given above. Therefore, with good policies, global warming should not be a significant problem. And with these same good policies, the people of the world will benefit greatly.
Tim Farage is a Senior Lecturer in the Computer Science Department at The University of Texas at Dallas. You are welcome to comment upon this blog entry and/or to contact him at email@example.com.