As the provider of biological energy and reduced carbon, photosynthesis provides a foundation upon which the biosphere and human society depend. Our food supply, our fibre, and much of our energy are derived from photosynthetic products. Photosynthesis gave rise to most of the energy used by industrialized societies, mainly in the bank of hydrocarbons that have accumulated in the Earth’s crust. As this fossil store of energy is depleted or, alternatively, if humans limit fossil fuel use to forestall global warming, people will face the challenge of replacing this ancient energy supply with renewable sources. In the form of biofuels, photosynthesis promises to be a major contributor to the new energy mix of a post-fossil-fuel world; however, this possibility raises the spectre of famine should resources be diverted from food production. Even without biofuels, food security will be a major concern for the coming decades since population and economic growth threaten to overwhelm existing supplies, while climate change, water depletion, land diversion to cities, and soil erosion threaten crop yields. To meet these challenges, agricultural production has to increase; however, in a world where much of the arable land is already in use, growing more on existing land and transforming non-arable into arable land are the principal strategies to enhance agricultural productivity. Increasing the output and efficiency of photosynthesis contributes to both objectives and thus has to be viewed as a strategic goal for future global security.
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