Global Warming: Scientific Basis and Christian Responses

Article excerpt

From the Book of Job, Chapter 38:1, 33-37:

1 Then the LORD answered Job out of the storm. He said:

33 Do you know the laws of the heavens? Can you set up God's dominion over the earth?

34 Can you raise your voice to the clouds and cover yourself with a flood of water?

35 Do you send the lightning bolts on their way? Do they report to you, "Here we are?"

36 Who endowed the heart with wisdom or gave understanding to the mind?

37 Who has the wisdom to count the clouds? Who can tip over the water jars of the heavens when the dust becomes hard and the clods of earth stick together?

   The era of procrastination, of half measures, of soothing and
   baffling expedients, of delays, is coming to its close. In its
   place we are entering a period of consequences--Winston Churchill,
   1936.

In the last twenty years, the science of greenhouse gases and global warming has moved from the often stuffy pages of academic journals to the front pages of newspapers and even to the movie theater. It has become the subject of international reports, (1) international conferences and protocols, (2) and Congressional hearings. It has become a divisive force in American politics and in American life, a division which has extended to the evangelical Christian community. The Evangelical Climate Initiative, representing one segment of the evangelical community has produced a statement that proclaims the reality of global warming and its serious consequences and the urgent need for evangelicals to respond. (3) In rebuttal, the Interfaith Stewardship Alliance claims that global warming, if happening at all, is natural and benign, and evangelicals should actively oppose any measures to mitigate it. (4) The result is that many citizens of the United States, including Christians, find themselves conflicted about the facts of global warming and the role of humankind in climate change.

In this article, it is my goal to address two broad themes. The first is the scientific basis of climate change, which I address by answering a set of science questions:

1. Is climate changing and, if so, on what time scale?

2. Do we understand the role of greenhouse gases in climate and climate change?

3. What is the impact of human activities on greenhouse gas concentrations compared to those of natural processes? Can these activities impact global climate?

4. Can we predict climate change during this century? What confidence should we have in such predictions?

The second theme is how evangelical Christians are responding to this issue. I attempt to categorize these responses under several headings. I end with my own personal response.

Is climate changing and, if so, on what time scale?

Earth scientists (a term which refers collectively to scientists interested in atmospheric sciences, oceanography, polar processes, geosciences, and Earth climate history) deal with a very broad range of time scales. This range separates into three categories: weather (one to fourteen days), climate (year to centuries), and geological time (thousands of years to millennia and beyond). (5) From a mathematical perspective, weather prediction is an initial condition problem. We specify a mathematical model of atmospheric fluid dynamics and associated physics, initialize that model with the current state of the atmosphere, and then integrate forward in time to predict the future state. Such predictive efforts, while very accurate in the time frame of a few days, decline in accuracy with time, generally failing to demonstrate any skill after about ten days. While we have extended the limit of useful prediction in the last few decades, there are real temporal limits to predictability due to our incomplete understanding of the weather system and our inability to specify completely and accurately the initial state of the atmosphere.

Climate, on the other hand, is a boundary condition problem. …