After all the icy weather we’ve had, the mention of global warming probably makes people roll their eyes. Bear with me, global warming is more than wishing for warmer weather. Understanding global warming takes patience, just as seeing its effects is a long term process. The first clarification to make is the difference between weather and climate. Weather is the day-to-day atmospheric conditions we experience. Climate, on the other hand, measures longer periods of time, years to decades. From yesterday to today the weather changes, from grandparents’ stories about winter to this year’s winter the climate changes. Just to underscore the changeability of weather remember, two days before the ice storm we had incredibly pleasant weather.
If global warming isn’t obvious in the weather, then where does it show up? It is evident in long term data. According to NASA, global average surface temperature has risen at least 1.4oF since 1880. There you go, the globe has warmed. The issue is what an increased temperature means to Earth’s ecosystems as a whole and what caused this increase. A single degree Fahrenheit increase doesn’t appear significant, but consider this: the human body responds to a fever of one or two degrees; likewise Earth’s ecosystems composed of multiple organisms respond to seemingly small changes. Small temperature increases immediately affect processes like plant germination and the way ice melts and feeds into streams, which in turn affects water availability throughout the year. Scientists predict other changes as temperatures rise, like increasingly intense weather, but models vary slightly in the severity they forecast.
These predictions are part of what makes global warming a controversial issue. Data do show that the earth has been warming for a time, but the future trends and the cause of the warming require interpretation by experts. Analysis of that data indicates warming is a trend that is likely to continue: by the end of the century, global temperatures are predicted to increase 2-10oF. Numerous factors influence weather patterns; accordingly, many different models exist to predict what changes will take place. Each model encompasses a different set of factors, so each forecasts a different amount of change. Those who deny the reality of climate change may use more conservative models to claim the effects of warming will be negligible (or they may challenge the idea that warming will continue at all). Critics also question the source of global warming, which is considered to be human emissions.
Humans affect the atmosphere by releasing large amounts of greenhouse gases, particularly carbon dioxide (CO2) and methane. At natural rates of release and reabsorption greenhouse gasses benefit Earth. These gases trap heat that reflects from Earth’s surface, keeping Earth at a constant, livable temperature. Excess greenhouse gasses are released when fossil fuels are burned. Since the Industrial Revolution began, and fossil fuels started being used intensively, carbon dioxide levels have increased nearly 38 percent and methane levels have increased 148 percent. The facts are, first, that CO2 and methane are greenhouse gasses that help warm the atmosphere, and, second, humans are releasing large amounts of these gasses into the atmosphere. Again, different models forecast a variety of results from increases in these gasses, but even the most mild prediction does not envision positive impacts. CO2 will keep rising as Earth’s population increases and those people burn fossil fuels to produce energy, power factories, and run cars.
These pieces of data point to a dire need for change; even the best case scenario will have severe impacts on crop growth, water availability, and animal life. While it may be presumptuous to say that humans are responsible for all components of global warming, it is equally presumptuous to assume that humans are completely innocent in the matter. Admitting global warming may be possible, but not threatening, perpetuates “a business as usual” attitude: why bother changing habits if threats aren’t serious? As stewards of creation, Christians are called to take responsibility for the way man impacts the environment. In the case of global warming, the parable of the talents (Matt. 25) seems particularly applicable. By unthinkingly loading greenhouse gasses into the atmosphere, we are not using our “talents” wisely. At best, this is tantamount to the steward who buries his talent: we certainly aren’t improving the environment through these practices; at worst, we are acting completely irresponsible and destroying what we have been given.
Care for creation isn’t the only motivator to avoid climate change: climate change will have a tremendous consequences for Earth’s human population. It will particularly affect those dependent on subsistence agriculture who aren’t able to migrate to new farming territory. Global warming is something to take seriously. The way individuals live their lives affects the earth itself. As caretakers of creation, Christians should keep in mind the impacts they have on creation itself and on others who inhabit creation.