EGEE 101
Energy and the Environment

What is uncertain?

PrintPrint

What we are uncertain about (most things)!

image of an avatar of a man

What is certain, is that climate change is occurring! That is about the only certainty when this subject is debated. There are a lot of uncertainties:

  1. Why it is happening: Natural or anthropogenic?

    Why it is happening: Text Version (click to reveal)

    Dr. Mathews: While we do agree that climate change is occurring, we are still debating what to call this. Certainly we have seen natural changes in the temperature and precipitation patterns in the past. The big debate is this anthropologic related due to man's activities or changing land use, the removal of the forests, from occupation or crops growing or is it perhaps a very natural event that is occurring as we have seen previously in the history of the planet. So we are still going to debate this. There are still a lot of interested parties however, saying that we don't know enough and that you don't want to make too many decisions that are going to impact the well being economically of the United States when there is so much uncertainty.

  2. Impact of snow and ice melting?

    Impact of Snow and Ice Melting: Text Version (click to reveal)

    Dr. Mathews: One of the reasons things are so uncertain comes because of feedback loops. Imagine this scenario, it warms up, snow melts. Because the snow melts it reveals more land. Well the land will warm up more because it is receiving more energy. When there is snow or ice on the ground, when there is sunlight, much of it gets reflected back up into space. When you go skiing, one of the key items of your equipment is goggles. Snow blindness is a very real threat because so much more light gets bounced from the surface into your eyes that in fact you can actually go blind. It is a very similar things with clouds. World War II pilots would wear sun glasses and if they are fighting in Europe it is not because of the English weather. When you are flying above clouds, again a lot of that light gets reflected back off the surface of the clouds because of the whiteness and it impacts how much energy reaches the surface of the planet. So back to the snow, snow melts, revealing more land the land warms up, the climate warms up, more snow melts. More snow melts, revealing more planet, more warmth from earth's land. This is a cycle. And it can happen the other way. We think ice ages, what happens is it snows, more energy is reflected. Then it gets warmer. Then it snows some more, more energy is reflected, the planet gets colder. It snows some more. A lot of these feedback loops will be happening and they can have a very drastic on how one assigns climate change models.

  3. Predictions are, well predictions.

    Predictions: Text Version (click to reveal)

    Dr. Mathews: Predictions are, well, predictions. We are not very good at telling the weather. When you are watching the Weather Channel they will tell you four days in advance and when there is a significant snow event coming we will see the snow falls change on an hourly basis. From the predictions from anywhere from we are going to get two feet of snow to we are going to get less then an inch. We are not very good at predicting the weather. What is going to happen is we are going to know if we are right 20, 40, 50 years from now. And there is a lot we don't understand. And the fear is that we are maybe jumping in too early, maybe by some. Others say the risks are worth it that we are probably going to help reduce pollutants in other areas as well and increase our energy efficiency. And it is going to have other benefits. But not much is certain in this area. So predictions, are well, just that. The computational models we use vary very widely from location to location and model and the assumptions that go into these models. So it is a very interesting subject.

Well, perhaps there are some other certainties. There will be a cost ($) to reduce pollution, or reduce energy use!

As more research has been performed there is much greater certainty that climate change is the result of human activities. From the Intergovernmental Panel on Climate Change (IPCC):

Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes. This evidence for human influence has grown since AR4. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century.