Ridgwell Andy, Singarayer Joy S, Hetherington Alistair M, Valdes Paul J
Bristol Research Initiative for the Dynamic Global Environment, School of Geographical Sciences, University of Bristol, Bristol BS81SS, UK.
Curr Biol. 2009 Jan 27;19(2):146-50. doi: 10.1016/j.cub.2008.12.025. Epub 2009 Jan 15.
The likelihood that continuing greenhouse-gas emissions will lead to an unmanageable degree of climate change has stimulated the search for planetary-scale technological solutions for reducing global warming ("geoengineering"), typically characterized by the necessity for costly new infrastructures and industries. We suggest that the existing global infrastructure associated with arable agriculture can help, given that crop plants exert an important influence over the climatic energy budget because of differences in their albedo (solar reflectivity) compared to soils and to natural vegetation. Specifically, we propose a "bio-geoengineering" approach to mitigate surface warming, in which crop varieties having specific leaf glossiness and/or canopy morphological traits are specifically chosen to maximize solar reflectivity. We quantify this by modifying the canopy albedo of vegetation in prescribed cropland areas in a global-climate model, and thereby estimate the near-term potential for bio-geoengineering to be a summertime cooling of more than 1 degrees C throughout much of central North America and midlatitude Eurasia, equivalent to seasonally offsetting approximately one-fifth of regional warming due to doubling of atmospheric CO(2). Ultimately, genetic modification of plant leaf waxes or canopy structure could achieve greater temperature reductions, although better characterization of existing intraspecies variability is needed first.
持续的温室气体排放导致气候变化达到无法控制程度的可能性，激发了人们寻求全球规模的技术解决方案以减少全球变暖（“地球工程”），其典型特征是需要昂贵的新基础设施和产业。我们认为，鉴于与可耕地农业相关的现有全球基础设施可能会有所帮助，因为作物植物由于其反照率（太阳反射率）与土壤和自然植被不同，对气候能量平衡有重要影响。具体而言，我们提出一种“生物地球工程”方法来减轻地表变暖，即专门选择具有特定叶片光泽度和/或冠层形态特征的作物品种，以最大化太阳反射率。我们通过在全球气候模型中修改规定农田区域植被的冠层反照率来对此进行量化，从而估计生物地球工程在近期的潜力，即在北美中部大部分地区和欧亚大陆中纬度地区实现夏季降温超过1摄氏度，相当于季节性抵消因大气CO₂浓度翻倍导致的约五分之一的区域变暖。最终，对植物叶蜡或冠层结构进行基因改造可能会实现更大程度的降温，不过首先需要更好地描述现有的种内变异性。
