I enjoy emails from readers of this site. My contact information is in the About page and the comments and encouragement I receive makes this site a joy to run. I recently received an email from Brittany C asking four questions. Brittany is allowing me to publish her questions and my answers. These answers are a combination of scientific fact with conjecture and opinion from me.
Question 1: Why is the warming that has taken place in this past decade been such a big deal when there seems to be a similar warming trend in the 1930s? Is there a difference between the two?
Great question. I am going to break it up into 3 parts:
Is it warmer this decade?
Why is the conversation increasing?
What is different now versus in the early 20th century?
First off, lets be clear, the warming in the last decade has probably been flat and there is some analysis that shows the last 10 years have been cooling slightly and the last 12 months has been pretty cold. It is difficult to really say that the trend has reversed because climate can only be measured in the long-term and the weather of last week, last month, or last year may be seen as just part of the average variation. Even a decade long trend needs to be examined if it is within average variation.
The bigger part of your question is why is it so prevalent in our culture today to discuss global warming. I think there are a couple reasons:
Books – There have been quite a few books on the subject but most of those books are very scientific and, frankly, have not influenced the average person. 2 books though are part of pop culture and have sold enough to have influenced the thought processes of many readers. They are Michael Crichton’s “State of Fear” (a book that has really propelled proponents and skeptics) and Tom Clancy’s “Skeleton Coast” where the bad guys are ultra-ecologists that believe in radical action to save the world.
United Nations – The UN’s Intergovernmental Panel on Climate Change (IPCC) has release several assessment reports and have claimed a huge number of scientists that have contributed in some way. The UN is not the most loved organization by many US citizens and that further fans the fuel of discussion. As I write this, there is a fairly contentiousmeeting being held to question and challenge the IPCC reports. All of this talk from learned people compels some coverage in newspapers, magazines, web sites, and blogs (like what you are reading now).
Technology – There is no doubt that much of this conversation has been more popular now due to the power of computers. We now have models that are beginning to be able to predict the climate. While this capability is only in its infancy and is still woefully lacking, the increase in power over what was available only 10 years ago is amazing. I contend that if we dedicate more resources to this effort, we will be able to truly predict our very chaotic climate.
Finally, what is different now compared to other times in the last 100 years or so? There are a couple major factors:
CO2 is increasing steadily. There is no reasonable discussion that carbon dioxide is not increasing. The Mauna Loa sampling site is pretty compelling. The mean value from 1959 was 315.98 ppm and the mean value for 2007 was 383.72 ppm. As we will discuss in some of your other questions, the concern is that CO2 will build up until we reach a tipping point which will cause the kind of devastation that was shown in “The Day After Tomorrow” and worried about in “An Inconvenient Truth”. Most people say that we are not at that tipping point today but the concern is that we are getting very close. Since that tipping point is only modeled in computers, you can see why I have repeatedly called for more research and investment in this area of study.
The prospect of accelerated increase in CO2 is very real. China and India are growing at massive rates. Their increased carbon dioxide output makes it that much more difficult to control that tipping point that I mentioned above.
I hope this helps to at least understand this first question. Brittany has asked three more questions. Check back later this week for that discussion.
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