A couple of months ago, I wore shorts as I biked to my office through the icy streets – not so common in mid-January in the middle of the Canadian prairies. Much more common is the phrase ‘So much for global warming!’, especially in the middle of weeks-long cold snaps when daytime temperatures don’t rise above -25 degrees Celsius (-13 F) and the nights are below -40 C. Obviously, the frigid temperatures shouldn’t come as a surprise. Saskatoon, Saskatchewan is in a high-latitude continental climate. Most winters are lived within an Arctic air mass, and we forget that many places on the planet are, at the moment, experiencing balmy temperatures.
Interestingly, I find this sort of cynicism about climate change especially prevalent among Christians. Why is this? I am reminded of what N.T. Wright spoke about here of a common tendency to group controversial issues under a guiding political umbrella. I definitely see this among many of my Christian friends on highly politicized topics, and climate change is no exception.
There is strong evidence that we have seriously changed the composition of a few chemical species in our planet’s atmosphere. The formation of the ‘hole’ in the ozone layer over Antarctica from the use of CFC refrigerants is one dramatic illustration.
As evident as this human impact on the atmosphere is, it is encouraging that – as a result of the 1989 Montreal protocol that enacted the phasing out of CFCs – there have been definite slowdowns both in the growth of the ozone hole and in global ozone depletion. This has given hope for recovery in the next 30 years as the depleting chemicals are cycled out of the atmosphere.
Warming and Cooling
Now fast-forward some twenty years. Just as there is evidence that we have affected the global distribution of ozone through injecting CFCs, there is equally convincing evidence that we are putting an ever-increasing amount of CO2 into the atmosphere. There is no doubt that we have fossil-fuel hungry, CO2-emitting lifestyles. The now-famous ‘Keeling curve’ illustrates the dramatic rise in atmospheric CO2 that is directly attributable to our burning of coal and fossil fuels in the past 250 years. From studies of past climates, there is no doubt that we are living in a period where atmospheric CO2 concentrations are as high as they have ever been. There is also no doubt that CO2 absorbs and re-emits back to the Earth a fraction of the infrared radiation that the Earth continually emits to ‘cool’ itself, the so-called ‘greenhouse effect’.
There are opposing factors that can mask this warming, such as sulfates in the stratosphere that produce an opposite, ‘cooling’ effect in the wake of strong volcanoes such as El Chichon (1983) and Mount Pinatubo (1991). In these two cases, the particles injected into the atmosphere by these eruptions were largely cycled out of the atmosphere a decade after eruption. The baseline story remains unchanged, that increased atmospheric CO2 means increased warming.
So what’s the issue? Why isn’t it clear that this is a problem and that we need to do something about it?
Part of what muddies the waters is the simple fact that earth’s climate is a complex system, to put it mildly. Without being able to run experiments on another planet, we rely on computer models. The massive atmosphere-ocean global climate models (GCMs) that are used to predict future climate can accurately capture long-term, global-scale phenomena such as El Nino reasonably well. The largest source of uncertainty in these models is the presence of many feedback cycles within the climate system. These intrinsic, unforced variabilities are seen in several elements of the climate system. To name a few, there are feedbacks in the light-absorbing characteristics of clouds and water vapor in the atmosphere, in the reflection of sunlight by ice cover, and from changes in land-surface sunlight reflectivity from changes in the land usage (i.e. forest becoming cropland).
Consider ice cover as an example. The area over the North Pole is covered by ocean, with a fraction of that area covered by ice. Ice reflects the majority of incident sunlight back to space, whereas water reflects back a much smaller fraction. Much of the remaining energy goes into warming up the water. Consider what happens when the amount of ice covering the northern seas slowly melts (as it is doing) from warmer air and/or ocean temperatures. Less ice to reflect sunlight back to space means more light strikes water, so the water slightly warms, so more ice melts, so there’s less ice to reflect sunlight back to space, … and so on. This is positive feedback: a change in the system leads to furthering that change.
Negative feedbacks also occur, where an affected component of the system will act to counteract the cause: negative feedbacks are a self-stabilizing process. My work focuses on studying high-altitude ice clouds. In the study of these clouds and their effects on climate, there are numerous interacting feedbacks, where even the nature (positive or negative) of the feedback itself is not clearly known. These are matters of intense current debate – the question of whether certain aspects of climate will stabilize or destabilize.
The highly political nature of the subject equally muddies the waters of climate change science. The complexity of the topic can rarely be sufficiently dealt with on a pedestrian level without great simplification. When it has become so politicized in the public mind, the facts are especially difficult to find – assuming that the facts are indeed sought. Neutrality is elusive. Our vested interests in this matter, in my mind, form a continuum. For most readers of these words, top-down implementation of mitigation strategies mean sacrifices and changes to our lifestyles. For those whose resources and dwellings could be threatened by a warming world, it’s not so much inconvenience as survival. It’s practically impossible not to have a vested interest. As one species – though not with equal contributions – we are having an unmistakable impact on factors that, to the best of our knowledge, regulate our planet’s climate. When will we know the full impact? Only time – twenty or fifty years’ worth – will tell.
What’s an appropriate response? Undoubtedly, top-down mitigation strategies are necessary, but are they enough? I believe that my daily choices and actions can have a definite effect on the world around me, and as a Christian, I believe that I will be held responsible. It’s clear to me that part of having been made in God’s image means that we act as responsible stewards of creation. What does that translate to in this context? One aspect is that we each live in the most responsible way with the available resources to ensure that others can also live to have the same opportunities. We are each responsible for the knowledge that we have. I believe there is a light we can show here as Christians. We have a call to simplicity of life that – though it is not the gospel – does resonate deeply with the words of Jesus, and that dovetails into these questions. How can we do a small part within our own sphere? By standing apart from the materialistic culture that convinces us that purchasing is the solution to every problem – from personal to mechanical to ecological.
I am the first to admit my need to re-organize my daily activities to minimize my ‘footprint’. As a typical North American, I use vastly more resources than the vast majority of people on earth. If everyone on earth lived the way I do, we would need 5-10 Earths to provide the necessary resources.
It seems that in any matter as complex as this, one’s clarity seems to be inversely related to the distance from it. But assuming that earth will take care of itself seems somewhat analogous to merging into traffic with eyes closed, believing that others will surely make way for me.