Those who are still undecided about whether or not climate change is occurring are now two steps behind the current discussion. Every informed opinion now accepts that global warming is certain and the debate is what we can do to mitigate the effects. The most current discussions are what we can do to adapt to the inevitable.
Those who are counting carbon recognize the indisputable trends. During the 1990s, the average rate of increase in human CO2 emissions was 0.7% per year; since 2000, the rate has risen to 2.9%. Levels of atmospheric carbon dioxide that were rising an average of 1.58% per year during the 1980s are at 1.93% durng the 2000s. A little more than a year ago, the proportion of CO2 in the atmosphere was 381 parts per million; it is now 385 ppm. Scientists from the UN's Intergovernmental Panel On Climate Change (IPCC) advise we have only eight years left to prevent the worst effects of global warming.
Three related trends have been noted during the last 30 years: more fossil fuels are being consumed as the global economy grows, China has been burning more coal, and rising temperatures are causing the planet's natural carbon sinks to lose their absorptive capacity – a shrinking half of all our emitted carbon dioxide will be absorbed into the land and oceans but an expanding proportion will stay in the atmosphere, each molecule continuing to advance global warming for about a century. As a consequence, levels of atmospheric CO2 are increasing about 35% faster than earlier predictions, with about 50% accounted for by additional emissions from China. This is the evidence encouraging the current discussions on adaptation.
Adaptation is not about slowing or stopping climate change. As scientist Sharon Begley writes in an environmental column in Newsweek (Dec. 31/07), "It's too late to stop global warming. Now we have to figure out how to survive it."
The title of her column, Learning to Love Climate "Adaptation", exudes irony. The love, if it's not the tough variety, will be akin to the affection we cultivated for a possible nuclear holocaust during the Cold War. And the quotation marks around adaptation are hers, suggesting that the process will be closer to endurance than relief.
Some of the adaptations may be surprising. An easy one will be lengthening the runways of airports. Lengthening the runways? Rising temperatures mean hotter air. Hotter air is less dense, thereby decreasing the lift of aircraft wings. So aircraft will need to take off and land at higher speeds, hence longer runways.
Another easy adaptation will be the addition to cities of special cooling centres, places where people can go for respite during heat waves. This service will be particularly useful for the aged since their bodies are less capable of adjusting to such adverse conditions.
A relatively easy adaptation will be the special dams we will have to build to halt "glacier lake outburst floods". The IPCC notes that these dramatic flows of water and debris caused by rapid melt and bursting ice dams can likely be contained by this added infrastructure. Such dams may even serve a dual function as reservoirs to help regulate more erratic water flow during extreme precipitation patterns.
In northern climates, as permafrost melts, vast stretches of roads will have to be rebuilt, relocated or abandoned. Northern villages will undergo the same choices as they sink. Although costly and disruptive, these will be fairly small disasters.
Other manageable challenges will be relocating or raising coastal highways as sea levels rise. Some bridges may have to be elevated and re-engineered to account for rising seas or more extreme water flow in rivers. Most highways will have to be designed to higher standards to account for more dramatic weather. Buildings, too, will need to be built to withstand more severe conditions. Many presently populated flood plains and estuaries will not remain habitable. Salt water from rising sea levels will contaminate coastal aquifers so new supplies of fresh water will have to be found.
Forest and grassland fires will be more common, requiring more sophisticated firefighting strategies, resources and equipment. Wooded areas that interface with dwellings will have to be managed more intensively because of elevated fire risk. This risk and higher insurance rates may disqualify some areas for building sites. Efforts to store the carbon that mitigates climate change may require that forests stay and people move. Adaptation will encourage greater densities of people to live within the more protective and efficient confines of villages and cities.
Warmer global temperatures mean greater moisture content in the air. This will translate into more intense rainfall and snowfall, and therefore more threat of floods, landslides and avalanches. Greater property damage will result from storms of increasing violence. Where a collision of cold and warm fronts occur, more ice storms will require that transmission lines be strengthened to account for the added weight.
"Although some adaptations will be modest and low tech...," writes Begley in her column, "others will require such herculean effort and be so costly that we'll look back on the era beginning in 1988, when credible warnings of climate change reached critical mass, and wonder why we were so stupid as to blow the chance to keep global warming to nothing more extreme than a few more mild days in March."
"Critical mass" was nearly 20 years ago. March is coming soon. And a hotter future is promised. This the context in which too many people and too many governments are still debating and dithering. The impatience in the air is more than just a yearning for spring.