There are people who suggest that global warming of a few degrees is nothing to worry about. Given the normal variability in weather from day to day and year to year, the temperature change would be hardly noticeable to humans. But many flora and fauna are far more sensitive to temperature than we are, and we mustn't forget that we are as dependent on ecological processes as any other species. Whether it's depletion of global fish stocks or the pollination of fruit by bees, or the myriad other known and unknown interactions that we depend on directly for food or economic activities, we are becoming ever more vulnerable to change.
Our growing population forces us to push the boundaries of efficiencies in food production in order to survive. In 1972, the Club of Rome published Limits to Growth, predicting that the human population would hit an upper limit as a result of limits to land, water and other resources needed for food production, and the ability of Earth to absorb pollutants. The assertion was that population grows exponentially, while the ability of technology to increase the availability of resources grows only linearly.
The collapse of our economy hasn't happened yet, as we have managed to harness technology to become more productive with what we have available; nevertheless we have overshot the carrying capacity of Earth's resources.
The 30-year update of Limits to Growth is no less pessimistic than the original.
The most common criticisms of the original World3 model were that it underestimated the power of technology and that it did not represent adequately the adaptive resilience of the free market. Impressive —and even sufficient— technological advance is conceivable, but only as a consequence of determined societal decisions and willingness to follow up such decisions with action and money.
Technological advance and the market are reflected in the model in many ways. The authors assume in World3 that markets function to allocate limited investment capital among competing needs, essentially without delay. Some technical improvements are built into the model, such as birth control, resource substitution, and the green revolution in agriculture. But even with the most effective technologies and the greatest economic resilience that seems possible, if those are the only changes, the model tends to generate scenarios of collapse.
One reason technology and markets are unlikely to prevent overshoot and collapse is that technology and markets are merely tools to serve goals of society as a whole. If society's implicit goals are to exploit nature, enrich the elites, and ignore the long term, then society will develop technologies and markets that destroy the environment, widen the gap between rich and poor, and optimize for short‑term gain. In short, society develops technologies and markets that hasten a collapse instead of preventing it.
Unfortunately, the more we rely for survival on efficient production from technological advance, the less resilience we have in dealing with set-backs.
Tight financial margins make a business more susceptible to shocks related to costs or market shifts; similarly, our reliance on industrial-scale farming, oil-based fertilizers, low food stockpiles and long shipping distances make it more likely that periods of food shortage will increase in certain countries. If disease or pests or extreme weather wipes out a crop, we have little reserve productive capacity to fall back on.
Climate change increases these risks, as this North American example illustrates clearly.
Forests can be a net "sink" of carbon, storing carbon dioxide as trees grow. They can also be a net "source" as their dead and rotting biomass emits carbon to the atmosphere. According to an article from Reuters (published in Business Report on 5 August), a third of the US land area is covered in forest, and forest growth in the US currently soaks up about 12 percent of the country's greenhouse gas emissions. That's a significant proportion. US forest area is only expanding by about 0.1 percent a year, partly because of competition for land for other purposes (including urban expansion and food production), and partly because of harvesting for lumber. But there is another significant threat from global warming that is already being felt.
Beetle infestations are destroying large areas of forest, with the double impact of lost income from timber harvesting and lost stores of carbon in pine and spruce trees. Beetle infestations are not new, but they are kept under control by cold winter temperatures that naturally kill off larvae under the bark. Warmer winters are allowing more larvae to survive.
Scientific observation stations in Medicine Bow National Forest are monitoring the rise and fall of atmospheric carbon in the forest every hour of the day. The US Forest Service's Glacier Lakes Ecosystem Experiments site was set up before beetle infestations became an issue, allowing direct measurement of the changes to carbon storage resulting from beetle infestation. Net carbon storage in this area is half what it was three or four years ago, and beetles are affecting millions of hectares of forest in the US and Canada.
If we, the human species, were not living so close to the edge of survival, the natural beetle cycles would not be a problem. We would not be needing the forests as a carbon sink, because we would not be needing to counter the forces causing climate change. We would have less of an impact on climate through our activities, and we would have greater resilience in adapting to natural variations in climate. It is only because we are living on the edge that we are having to fight so hard to maintain the status quo in climate and biodiversity. It is our intense pressure on resources, and low tolerance for change, that make long-term climate trends - or even seasonal variations in temperature - a global economic challenge.
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