Is God green?
Climate change and the Scriptures
Dr. Jim Denison
Global warming is one of the most divisive subjects of our day. Some allege that the entire issue is overblown. Others claim that it is the most crucial moral and practical issue of our time. What are the facts behind the debate? What does the Bible say to this critical subject?
Learning the vocabulary
“Weather” refers to the atmospheric conditions on a given day; “climate” describes these conditions over an extended period such as a decade or more. The “weather” can be good today, but the “climate” can change in ways which are frightening.
“Climate change” is used synonymously with “global warming,” but the National Academy of Sciences says that “climate change” is becoming the preferred term. Rising temperatures are the best known symptom of the issue, but they are not the entire problem.
“Climate change” refers to any significant change in measures of climate (temperature, precipitation, or wind) lasting for an extended period (decades or more). It may result from:
Natural factors, such as changes in the sun’s intensity or slow changes in the Earth’s orbit around the sun
Natural processes within the climate system, such as changes in the ocean and its circulation
Human activities which change the composition of the atmosphere (such as burning fossil fuels) and the land (such as deforestation, urbanization, desertification).
“Global warming” refers to an average increase in the temperature of the atmosphere near the Earth’s surface, contributing to changes in global climate patterns. Most people use the phrase to refer to increased emissions of “greenhouse gases.”
“Greenhouse gases” have been produced over the last 200 years. Burning fossil fuels produces carbon dioxide. Farming practices and land use changes produce methane and nitrous oxide. Trees remove carbon dioxide, replacing it with oxygen; deforestation lessens this effect in the atmosphere. As a result, greenhouse gases have risen significantly. They prevent heat from escaping to space, similar to glass panels of a greenhouse.
The “greenhouse effect” helps regulate the Earth’s temperature. Without these insulating gases insulating the Earth’s surface and trapping solar energy which would otherwise escape into space, temperatures would be about 60 degrees colder than they are now and life could not exist. However, the burning of fossil fuels and deforestation have enhanced this natural greenhouse effect, causing the Earth’s average temperature to rise.
“Ozone” (also called trioxygen) is a molecule consisting of three oxygen atoms. It is found near the ground and also in the upper atmosphere. Its primary significance for climate change and health has to do with its ability to absorb ultraviolet light and energy. It is produced in the atmosphere when ultraviolet light interacts with oxygen.
The “stratosphere” or “ozone layer” exists between six and 31 miles above the ground. In general, the ozone layer is thinner near the equator and thicker toward the poles, and it varies with season, being thicker during the spring and thinner during the autumn in the northern hemisphere. The ozone layer filters out ultraviolet light from the Sun which would be harmful to most forms of life. If the entire ozone layer were compressed to the pressure of air at sea level, it would be only a few millimeters thick.
Has there been global climate change?
Climate change has occurred throughout the Earth’s history. Changes in the Earth’s orbit and tilt are thought to have led to the Ice Age around 21,000 years ago. Between 900 and 1300 AD, the planet was relatively warm. Cooling of the Sun led to a “little ice age” in the 1400s to 1800s, where global temperatures were cooler than normal. Volcanic eruptions emit aerosols and carbon dioxide into the atmosphere. Aerosols contribute to short-term cooling, but they are soon dissipated. For instance, an eruption in Indonesia in 1815 lowered global temperatures by as much as five degrees.
Volcanoes also emit carbon dioxide. For two-thirds of the last 400 million years, CO2 levels and temperatures were much higher than the present. However, human activities now emit 130 times as much CO2 as volcanoes.
We are now in the third climate change period of the last 2,000 years, and by far the most significant. Beyond dispute, the Earth’s temperature is climbing. According to data from NASA and NOAA, the Earth’s average surface temperature has risen by about 1.2 to 1.4 degrees Fahrenheit in the last century. The eight warmest years on record since 1850 have all occurred since 1998; the warmest was 2005. Temperatures at many individual locations were higher in the last 25 years than at any period of comparable length since AD 900.
What has caused global climate change?
“El Nino” is the strong warming of the Pacific Ocean near the equator; this occurs every two to seven years. Recent El Nino events have been very strong, contributing to record-setting temperatures. We’re not sure how much human-induced climate changes might affect El Nino, or the reverse.
Variations in the Earth’s orbit and tilt, and in the Sun’s heat, have caused climate changes over the Earth’s history. But except for the Ice Age, none brought anything like the devastation we are now seeing. And the human contribution to this crisis is beyond dispute.
The ozone layer
The ozone layer can be depleted by nitric oxide, hydroxyl, atomic chlorine, and atomic bromine. Concentrations of chlorine and bromine have increased significantly in recent years due to the release of large quantities of chlorofluorocarbons (called “freons”) and bromofluorocarbons (called “halons”) into the atmosphere. They rise into the stratosphere, where they interact with ozone molecules and break them down.
“Freons” were invented in the 1920s, and were used in air conditioning units, as aerosol spray propellants, and in cleaning electronics. They also occur as by-products of some chemical processes. No significant natural sources have ever been identified for these compounds; they are almost entirely manmade. A single CFC molecule takes 15 years to reach the upper atmosphere, where it stays for a century and destroys up to 100,000 ozone molecules. When the effect of these gases was finally understood in the 1980’s, they were phased out and have not been produced in large quantity since 1996.