The message is clear and undebateable: climate change is real, and unavoidable - and unless drastic cuts are made to GHG emissions between now and 2050, the consequences will be dire for the next 1000 years. Last night, to a packed house in the University of Winnipeg's Riddell Hall, Dr. Andrew Weaver made this point in a one-and-a-half hour survey course of current climate change science, touching on everything from homeostatic feedback loops and thawing tundra, to climate change modelling and future scenarios. From 1824, when Fourier first described the global greenhouse effect, to a 2050's nuclear/hydrogen future, Dr. Weaver painted a compelling verbal tableau of a global community struggling to balance adaptation and mitigation, an erroneous media dialog, and a critical need for action.
Dr. Weaver began with his namesake activity - weaving together ice-core data, the historical science of Fourier and Arrhenius, and climate modelling to describe the unambiguously anthropogenic causes of climate change. While climate change is a constant in both geological and human timescales, in the past has been attributeable to planetary orbit and axial tilt, and point-in-time events like volcanic erruptions. Changes in the amount of solar energy received over time have historically driven the equilibrium between temperature and CO2, and the resulting climate and ecologies. The industrial hockey-stick that we are currently living in breaks this pattern: CO2 levels are for the first time in 650,000 years preceeding temperature change, rising independent of insolation, driven not by geology or orbital dynamics, but power generation, combustion engines, and industry.
The implication is that climate change is coming, regardless of what steps are taken now. All of the climate change models in use agree - significant warming (from 2 - 6 degrees celsius), is happening now - centered in the northern latitudes, predominantly over land. Feedback loops are in play - a slowly warming sea, decreasing albedo from reduced snow cover, thawing permafrost, and so on ensure that we have passed the threshold inevitability. All evidence consistently agrees that this is in fact happening, argues Dr. Weaver - sea levels are rising, average temperatures are on the increase, ice is melting and so on. Where deniability thrives, however, is in the realm of human perception: with each of our reference frames defined by our local conditions on a day-to-day basis, the bigger picture is difficult to perceive.
Dr. Weaver argues that our perceptions are further clouded by the combination of mainstream media's obsessive need to find "both sides" of any given story, and climate change denialist's willingness to exploit that need. Denialist's win not by discrediting climate change, but by creating the perception in the public mind that the reality of climate change is still a topic of scientific debate. While this is no longer the case among the scientific community (who's belief in climate change, as consolidated by the IPCC, is unanimous), entrenched political interests have no difficulty finding experts of questionable credibility willing to speak publically to their political agendas. The inference that Weaver leaves the audience to make is that this perceived scientific indecision allows the current social/economic/industrial status quo to persist to the great benefit of the usual suspects - Cheney, big business, big oil.
Dr. Weaver's position is that in the next 43 years - by 2050 - this three-way game of cat and mouse between industry, science, and media needs to stop. If CO2 levels can be reduced by 60 - 90% before 2050, massive climate change can be averted. If not, we are entering 2000 years of pain - average global temperature increase of 8 degrees or more, the melting of the greenland icecap (raising sea levels by 6-7m), carbon saturation and acidification of the oceans, and an extended litany of horrors. Dr. Weaver demonstrates that past successes show that this goal is achievable - the Montreal Protocol on CFC's in 1987, for example, has been successful and sets a precedent for a globally united effort. Certainly reducing CO2 emissions by such a degree is a large dragon to slay, but Dr. Weaver argues that the technologies (nuclear, solar, fuel cells) are in place to make it happen when public need and political will catch up ecological reality.
One particular point that stood out for me in Dr. Weaver's presentation was that "climate" is the statistical study of weather, and that "climate change" is a shift in the distribution of likely weather at any given point. What that shift in distibution means is that extremes become more likely at the upper end of the distribution - extreme heat, extreme precipitation or drought, and so on. This gradual pattern is difficult for a layperson to discern as the lense of our personal reference frame (see above) doesn't buffer enough data to allow us to mentally plot a distribution for ourselves (pardon the pseudo-IS analogy). I've long had a fuzzy notion that an increase in global average temperature translates to chaos on a local scale, but Dr. Weaver made this concept and the science behind it simple to grasp.
Dr. Weaver left the room with a message familiar to WorldChangers: climate change is reality, and we collectively have the power to deal with it - if the public, media, and politicians will just bloody well move on from the debate already.
