2030年“土地退化零增长”目标下我国沙漠化防治的空间布局与成本估算

United Nations Conference on Sustainable Development that held in 2012 had proposed a new sustainable development goal named “Zero Net Land Degradation”, which is planned till to 2030 and aims to secure the contribution of our planet’s land and soil to sustainable development. As one of the countries that seriously suffered from land degradation in the world, Chinese government should focus on this new global vision and make related national strategy by considering the actual characters of land degradation, especially make clear of spatial planning and cost estimation for land degradation prevention to achieve the goal of “Zero Net Land Degradation” in 2030. In China, sandy desertification is the most important land degradation type, and the sandy desertification land accounts 18.03% of the total land of China. Although land sandy desertification had been reversed in some regions under the ecological protection engineer launched by national and local government, the situation of sandy desertification controlling is still serious. So, this project selects sandy desertification as the research object, basing on developing the sandy desertification system dynamic model at national scale, the dynamics of sandy desertification in 2030 under different scenarios would be simulated and the sandy desertification controlling demand would be calculated by selecting 1980s as the baseline period. Based on above, the spatial planning for sandy desertification controlling would be made by considering the sensitivity of land sandy desertification, the suitability for sandy desertification rehabilitation and the value of ecosystem service of land. Meanwhile, the cost for sandy desertification controlling would be estimated by considering both direct cost and the added value of ecosystem service from land rehabilitation. The implementation of this project can not only provide a systematic referencing scheme for China to achieve the goal of “Zero Net Land Degradation” in 2030, but also support the sandy desertification controlling in future, which has a great significance.

2012年召开的联合国可持续发展大会提出到2030年要实现“土地退化零增长”的愿景目标，作为世界上受土地退化影响最为严重的国家之一，我国有必要围绕这一目标并结合我国土地退化实际情况来探讨未来的防治布局与资金需求。因此，本项目以沙漠化这一我国面临的最大的土地退化问题为研究对象，通过建立适用于国家尺度沙漠化模拟的系统动力学模型来预估不同情景下2030年我国沙漠化发展态势，并以上世纪80年代为基准期来确定我国沙漠化防治需求；在此基础上，综合考虑沙漠化土地敏感性、可治理性以及治理区域的生态系统服务价值，识别未来沙漠化防治的重点区域；并将沙漠化治理的直接成本与生态系统服务价值相结合，合理估算沙漠化防治的成本。该项目的实施不仅可以为我国实现2030年 “土地退化零增长”目标提供一体化的参考方案，也可以科学的支撑我国未来沙漠化防治工作的开展，具有十分重要的意义。

土地退化影响着全球可持续发展和社会稳定，而沙漠化是我国涉及面最广、最为严重的土地退化问题。为实现2030年“土地退化零增长”目标，我国有必要根据未来沙漠化发展态势和治理需求，科学规划沙漠化防治的空间布局并合理估算防治成本，制定综合性的沙漠化防治战略。.本项目基于以往沙漠化监测和气候变化影响评估相关成果，系统收集整理了中国北方沙区自然环境和社会经济数据，基于VENSIM平台和Python语言建立了国家尺度沙漠化模拟空间系统动力学模型，并对模型模拟结果进行验证；模拟不同情景下2030年我国沙漠化格局及演变趋势，按照“土地退化零增长”标准开展沙漠化防治需求分析；基于沙漠化土地敏感性、可治理性及治理区域的生态系统服务价值，定量评估未来沙漠化防治的优先程度，识别我国北方沙区沙漠化重点防治区域；综合考虑直接成本和生态系统服务价值，结合沙漠化防治重点区域的特点，对不同情景下沙漠化防治成本进行估算。.结果表明：（1）中国北方沙漠化由东向西趋于严重。未来沙漠化总体上呈现逆转趋势，逆转面积占20%以上，积极的治理政策使沙漠化逆转速度加快，与湿润的气候条件叠加使90%以上的沙区更有利于实现“土地退化零增长”目标；若气候趋于干旱，消极政策会使得沙漠化发展面积占比近37%。（2）沙漠化防治重点区域主要沿东北-西南方向分布在研究区东部，主要包括科尔沁草原、察哈尔、乌兰察布、土默特与晋西北地区等，这些区域自然条件相对较好，同时经济发展与人为干扰强度相对较高。（3）沙漠化治理的直接成本受人类活动影响，积极治理情景下直接治理成本最高；间接治理成本方面，防风固沙生态系统服务价值>人工林耗水成本>碳汇生态系统服务价值，湿润的气候条件和积极的治理政策是未来沙漠化治理成本提高的关键因素。.本项目的实施明确了我国未来沙漠化防治的空间布局和资金需求，不仅可以为我国实现2030年“土地退化零增长”目标提供一体化的参考方案，也可以科学的支撑我国未来沙漠化防治工作的开展，具有十分重要的意义。