Nature Sustainability  | 利润驱动的耕地扩张与保护政策的影响

文章标题：Effects of profit-driven cropland expansion and conservation policies

标题译文：利润驱动的耕地扩张与保护政策的影响

发表期刊：Nature Sustainability 

在线时间：2024-08-13

通讯作者：Julia M. Schneider ;  Florian Zabel

作者单位：Department of Geography, Ludwig-Maximilians-Universität München, Munich, Germany.

全球农业扩张可能会对生物多样性和气候变化产生重大影响，尤其是在未来的耕地扩张压力下。尽管全球有着缩小当前产量差距和减少耕地面积的巨大潜力，但许多地区的耕地仍在扩大，尤其是在非洲和南美洲。这种扩张加剧了自然栖息地的丧失和破碎化、碳排放、以及生物多样性的进一步恶化。因此，识别未来耕地扩张压力最大的区域对于确定可能产生最强烈权衡的热点区域至关重要。

本研究采用了一个跨学科耦合模型（iLANCE），结合了环境条件、模拟的作物产量、土地利用变化的社会经济驱动因素以及区域经济条件，识别到2030年全球耕地扩张压力最大的区域。在此基础上，研究分析了在3.6%全球耕地扩张情景下，对农业市场、生物多样性和二氧化碳排放的潜在影响。此外，还评估了全球保护政策可能如何转移扩张压力并改变随之而来的影响。

• 耕地扩张压力主要集中在热带地区，特别是中非国家和南美洲的巴西和阿根廷等地

• 3.6%的耕地扩张将使全球农业产量增加2%，但同时也会产生17.1亿吨的二氧化碳排放，并导致扩展区域内生物多样性完整性进一步下降26%。

• 保护政策禁止将森林、湿地和现有保护区转为耕地，可显著减少因土地利用变化产生的排放，维持全球农业生产力，但可能对生物多样性产生相反的效果。

Fig. 1 | Areas under expansion pressure up to a potential increase in current cropland of 30% without conservation policies. a, Pixel-based profitability ranking of expansion areas, indicating under which global cropland expansion (1% to 30%) a pixel is among the globally most profitable ones to be transformed into cropland. Grey areas display current cropland. b, Regional distribution of the most profitable expansion areas displaying the regional area shares and the potential relative expansion of up to 30% of current cropland within each region.

Fig. 2 | Areas under expansion pressure in the 3.6% EXP scenario. a, Regional distribution of areas under expansion pressure and their global shares in the total area under pressure. b, Global cumulative distribution of area under expansion pressure (%) at pixels with shares from 0% to 100% currently covered with cropland.

Fig. 3 | Economic impacts of converting the areas under expansion pressure into cropland until 2030 in the 3.6% EXP scenario vs the REF scenario. a, Relative changes in producer prices and production (%) per region. b, Relative changes in the GDP (%) for the 21 economic regions, distinguishing between net exporters and net importers. The size of the dots represents the absolute GDP of the regions under the EXP scenario in 2030. The region mapping and abbreviations of the economic regions can be found in Extended Data Fig. 3.

Fig. 4 | CO₂ emissions generated by converting the areas under expansion pressure into cropland in the 3.6% EXP scenario. a, Shares of the different cover types (primary, secondary, pasture) and PNV types on the global area under expansion pressure (top) and the generated CO₂ emissions (bottom). b, Regional distribution of the generated CO₂ emissions in absolute terms (Gt CO₂).

Fig. 5 | Regional impacts of the transformation of the areas under expansion pressure into cropland on biodiversity in the 3.6% EXP scenario. a, Regional biodiversity intactness and its changes due to cropland expansion. The shaded circles display the BII across the areas under expansion pressure under current land use (Reference BII) and under their use as cropland (Expansion BII). Moreover, the regional change in BII (%) from the reference to the respective scenario is displayed as a percentage. b, Area (thousand km²) identified to be under expansion pressure in the world’s most threatened biodiversity hotspots49 under the 3.6% EXP scenario.

Fig. 6 | Changes in the spatial patterns of expansion pressure and the socio-economic and environmental impacts under the implementation of conservation policies. a, Spatial shift in areas under expansion pressure for the identified areas up to an increase of current cropland by 30% (4.27 million km2 ) as a defined upper boundary. Brown areas have been identified to be under expansion pressure without the consideration of conservation policies, but are protected by the assumed conservation policy; green areas are the areas into which expansion pressure shifts under conservation policies; grey areas are under expansion pressure with and without conservation policies. b, Relative changes in area under expansion pressure (%), GDP (%), BII impact (%) and CO2 land-use emissions (%) between the expansion scenarios with (CON scenario) and without (EXP scenario) conservation policies under a global expansion of 3.6%, for selected economic regions (see Extended Data Fig. 3 for region mapping).