Joint Program on the Science and Policy of Global Change, Massachusetts Institute of Technology, 77 Massachusetts Avenue, MIT E19-411, Cambridge, Massachusetts 02139, United States.
Environ Sci Technol. 2012 Jun 5;46(11):5672-9. doi: 10.1021/es2034729. Epub 2012 May 18.
Land can be used in several ways to mitigate climate change, but especially under changing environmental conditions there may be implications for food prices. Using an integrated global system model, we explore the roles that these land-use options can play in a global mitigation strategy to stabilize Earth's average temperature within 2 °C of the preindustrial level and their impacts on agriculture. We show that an ambitious global Energy-Only climate policy that includes biofuels would likely not achieve the 2 °C target. A thought-experiment where the world ideally prices land carbon fluxes combined with biofuels (Energy+Land policy) gets the world much closer. Land could become a large net carbon sink of about 178 Pg C over the 21st century with price incentives in the Energy+Land scenario. With land carbon pricing but without biofuels (a No-Biofuel scenario) the carbon sink is nearly identical to the case with biofuels, but emissions from energy are somewhat higher, thereby results in more warming. Absent such incentives, land is either a much smaller net carbon sink (+37 Pg C - Energy-Only policy) or a net source (-21 Pg C - No-Policy). The significant trade-off with this integrated land-use approach is that prices for agricultural products rise substantially because of mitigation costs borne by the sector and higher land prices. Share of income spent on food for wealthier regions continues to fall, but for the poorest regions, higher food prices lead to a rising share of income spent on food.
土地可以通过多种方式用于缓解气候变化，但特别是在环境条件不断变化的情况下，这可能会对食品价格产生影响。我们使用综合全球系统模型，探讨了这些土地利用选择在稳定地球平均温度在工业化前水平 2°C 以内的全球减排策略中所扮演的角色，以及它们对农业的影响。我们表明，包括生物燃料在内的具有雄心的全球仅能源气候政策可能无法实现 2°C 的目标。一个理想的全球土地碳通量定价实验，再加上生物燃料（能源+土地政策），可以使世界更接近这个目标。在能源+土地情景下，通过价格激励，土地可能在 21 世纪成为约 178 PgC 的大型净碳汇。在没有生物燃料的情况下（无生物燃料情景），碳汇与有生物燃料的情况几乎相同，但能源排放略高，从而导致更多的变暖。如果没有这些激励措施，土地要么是一个较小的净碳汇（仅能源政策为+37 PgC），要么是一个净源（无政策为-21 PgC）。这种综合土地利用方法的显著权衡是，由于该部门承担的缓解成本和更高的土地价格，农产品价格大幅上涨。较富裕地区用于食品的收入份额继续下降，但对于最贫困地区，较高的食品价格导致用于食品的收入份额上升。
