Unlike the subject of global warming, the subject of land use is not easy to sensationalize, or even define. However, it is an equally critical issue, and equal effort must be devoted to addressing it. Global warming can be defined and addressed using only two externalities, GHG emissions and destruction of carbon sinks. Land use is much more complex, and will require a more multifaceted explanation. I will start with a look at the externalities created through land use. I would suggest that the negative externalities related to land use include the following:
1. Decrease in carbon sinks due to land use change affects atmospheric carbon
2. Destruction of habitat damages ecosystems and biodiversity and subsequently affects quality of life
3. Desertification is reducing land available for agriculture or conservation
4. Deforestation for agriculture is causing erosion and infertility in nutrient-poor soils
5. 98% of the world's arable land is already under cultivation. This means that the 50% more people that will be alive in 40 years will be difficult to feed (really an externality associated with population growth, but can be addressed as a land-use issue)
6. Damage caused by the use of pesticides and other chemicals in agriculture
7. Depletion of fresh water reserves through use of extensive irrigation in agriculture.
8. The distribution of human populations and demand for uniform product availability forces expensive and environmentally damaging infrastructure & transportation costs, as well as increased use of food processing & preserving techniques (again, an externality associated with population distribution, but related to land use)
9. Damage to key biomes like rainforest, coral reefs and wetlands are reducing valuable "ecosystem services" like watershed management, nitrogen fixation and waste treatment.
Not all of these externalities are going to be able to be 100% eliminated, and I would not advocate such steps even if it was possible. Entirely mitigating these externalities would result in a radical chnage in human existence, and would fundamentally alter the world economy. I instead advocate a series of steps designed to gradually shift human society toward a more sustainable model and to blunt some of the most destructive effects of human land use without inflicting serious economic harm.
I also feel as though I should disclose my ultimate vision for what the sustainable earth of the long-term future would look like. Significant technological improvement and social change is a prerequisite for this vision, and I believe that even if the vision was universally adopted, its implementation would take a century or more. I simply present it as a template to model policy after, because without such a goal, I don't believe a complex policy approach can be successful.
My future Earth would be one of "urban islands" within a largely unspoiled landscape. Assuming a stable, long-term population of about 9 billion, I think about 8 billion could be housed within approximatley 6500 cities, of which the vast majority would have populations around 1-2 million, but where around 200 would be megaopolises with populations of 10m or greater. The remaining billion people would remain in rural areas in order to undertake tasks that cannot be centralized (such as mining or hydroelectric power generation). This would represent a fall in the earth's rural population by 2/3.
With that level of urbanization, significant portions of land could be returned to their natural state. In my ideal future world, 50% of the world's land would be returned to a pre-human state, with no human impact except for tourism (hopefully eco-tourism). Included in this 50% would be at least 50% of original (pre-agriculture) land area of each of the Earth's 14 terrestrial biomes. (For a list of the terrestrial biomes, see wikipedia). Additionally, any region defined as a biodiversity hotspot would recieve additional attention and an attempt would be made to restore as much of the original area as feasable (without knocking down cities).
For some biomes, this will be easy. Far less than 50% of the Earth's tundra and boreal forest have been substantially affected by human activity. Keeping it that way should be fairly painless, as most of the land does not have substantial economic value. Other biomes, like wetlands and rainforest, are going to be substantially more difficult. Many of these biomes have already lost more than 50% of their orginal land area and achieving the goals I have set out would require the reduction of human land use.
A reduction in human land use will require changes in agriculture. The vast majority of non-urban land modified by human activity has been for agriculture of some kind. In order to move towards increasing the "wild lands" of the Earth, agriculture must change. Coincidentally, demographics are going to force it to change anyway, so the time is ripe if this change can be managed in a positive way.
Given the externalities to mitigate, the goals I have set out and the realities of the situation, there is at least some basis for the beginnings of a policy framework. I will discuss policies here that are specific to Canada, although many of them can be adapted for usage elsewhere.
1. In 2003, approximatley 6.3% of Canada's land area was classified as "protected" by the IUCN. The global average is 10.8%. I believe that the government should endeavour to bring Canada's percentage up to the global average within ten years (and gradually increase it thereafter). This would be done by enlarging existing preserves or creating new ones, with the biomes that have been most reduced in Canada being the primary targets for conservation. Additionally, lands currently under cultivation that are only marginally arable (require massive amounts of irrigation, fertilizer or pesticides) should be targeted for purchase and restoration to orginal status.
2. A study should be done to examine the various ways of implementing a system of urban "vertical farming" (see http://www.verticalfarm.com/). If studies show such a system to be feasable with limited government support and without violating Canada's free trade agreements, development programs should be put in place immediately. I believe that the system will turn out to be economical at large enough scales, especially for crops that are usually imported from a long ways away, and will provide a much less envrionmentally damaging form of agriculture, since most inputs can be recycled and pesticides become unneccessary. Incedentally, a vertical farming program also has the potential to create many high-skill jobs in Canada, and should provide better quality, fresher food.
3. Incentives should be provided to encourage population consolidation in Canada, both within urban areas and overall. Urban development projects that create high density communities served by efficient public transit should be promoted, while excessive suburbanization should be discouraged. A second set of incentives should be provided for people to move from small towns into larger towns or cities. Associated with this migration will neccessarily have to be a further consolidation of agriculture so that the work can be done with fewer people.
4. Within both existing and new forms of agriculture, research grants should be set up for projects aiming to increase the nutritional content or yield of crops, or to decrease the needed water, fertilizer or pesticides. Genetically engineered crops combined with vertical farming offer the long term potential to drastically reduce our need for traditional agriculture and the associated land use and other environmental problems.
5. Canada should take the lead in promoting sensible solutions for land use issues worldwide. Canada, due to its low population density, high urbanization, technological prowess and abundant supplies of fresh water, is not the country where most of these land use issues are most critical. It is important that we keep in mind that we are citizens of the world as well as of Canada, and advocate for similar changes to those above in other countries of the world.
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