Substantial impacts of landscape changes on summer climate with major regional differences: The case of China

Cao Q. et al., 2018. Science of the Total Environment

Original research (primary data)
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Abstract

China’s rapid socioeconomic development during the past few decades has resulted in large-scale landscape changes across the country. However, the impacts of these land surface modifications on climate are yet to be adequately understood. Using a coupled process-based land-atmospheric model, therefore, we quantified the climatic effects of land cover and land management changes over mainland China from 2001 to 2010, via incorporation of real-time and high-quality satellite-derived landscape representation (i.e., vegetation fraction, leaf area index, and albedo) into numerical modeling. Our results show that differences in landscape patterns due to changes in land cover and land management have exerted a strong influence on summer climate in China. During 2001 and 2010, extensive cooling of up to 1.5 °C was found in the Loess Plateau and 1.0 °C in northeastern China. In contrast, regional-scale warming was detected in the Tibetan Plateau (0.3 °C), Yunnan province (0.4 °C), and rapidly expanding urban centers across China (as high as 2 °C). Summer precipitation decreased in the northeastern region, with patchy reduction generally b 1.8 mm/day, but increased in the Loess Plateau, with local spikes up to 2.4 mm/day. Our study highlights that human alterations of landscapes have had substantial impacts on summer climate over the entire mainland China, but these impacts varied greatly on the regional scale, including changes in opposite directions. Therefore, effective national- level policies and regional land management strategies for climate change mitigation and adaptation should take explicit account of the spatial heterogeneity of landscape-climate interactions.

Case studies

Basic information

  • Case ID: INT-236-1
  • Intervention type: Created habitats
  • Intervention description:

    GFGP ... extensive areas of cultivated fields and overgrazed lands (135,000 km2) were converted to woodlands in the central part of the nation due to the Grain to Green Program....in the southwest cultivated and overgrazed lands were turned into shrublands

  • Landscape/sea scape ecosystem management: Yes
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Other climate impact  Mixed results Other = changes in local precipitation Measure = summertime precipitation (simulated and observed)
    Other climate impact  Mixed results OTH=air temperature Changes in 2m air temperature (assessed through modeling and observational data at meteorological stations)
  • Approach implemented in the field: Yes
  • Specific location:

    Southwest of the Loess Plateau

  • Country: China
  • Habitat/Biome type: Created forest | Created grassland | Created other |
  • Issue specific term: Not applicable

Evidence

  • Notes on intervention effectivness: To assess effectiveness: Change over time "We designed two numerical experiments to analyze impacts of land- scape change on China's summer climate. One represented 2001 land- scape (hereafter LS2001) by using 2000 land cover data (in lieu of 2001, which was unavailable) and 2001 biophysical properties (i.e., vegetation fraction, LAI, and surface albedo). The other denoted 2010 landscape (hereafter LS2010) by using 2010 land cover data and 2010 biophysical properties. To better distinguish the signal of land- scape change-induced forcing, we selected a normal monsoon year as driving meteorology based on examination of the East Asian summer monsoon index " --> used these to simulate changes in 2m air temperature and precip and then validated with actual observed values from meteorological stations to confirm contributions of land-use/management change to climate Mixed for change in temp: "Although revegetation in the Loess Plateau gave rise to increased biomass and thus extensive summer cooling, an exception existed at the southwest of the region, where cultivated fields and overgrazed lands have been converted to shrublands since the implementation of the Grain to Green Program. Consequently, 2-m air temperatures in- creased in summer owing to decreased latent heat flux but increased sensible heat flux." ... "patchy increases in 2-m air temperature, on the order of 0.2–0.4 °C, were simulated at the southwest of the region." Mixed for precipitation: negative in the southwest of the loess plateau and dont report for the rest of it (although shows increasing trend in the loess plateau, don't make statement about contribution of the intervention) "In addition, minimal changes in summer precipitation were simulated there, while the observations revealed a downward trend. This was because the replacement of grasslands by woody plants in water-limited areas restricted the growth of woody plants and thus the evapotranspiration of vegetation through which regional climate was regulated. Therefore, afforestation in arid and semiarid areas should proceed with caution"
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: No
  • Impacts on GHG: Not applicable
  • Assess outcomes of the intervention on natural ecosystems: No
  • Impacts for the ecosystem: Not reported
  • Ecosystem measures:
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures:
  • Considers economic costs: No
  • Economic appraisal conducted: No
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Quantitative
  • Is it experimental: No
  • Experimental evalution done: Not applicable
  • Non-experimental evalution done: Empirical case study
  • Study is systematic: