Trends in Global Vegetation Activity and Climatic Drivers Indicate a Decoupled Response to Climate Change

PLoS One. 2015 Oct 14;10(10):e0138013. doi: 10.1371/journal.pone.0138013. eCollection 2015.

Abstract

Detailed understanding of a possible decoupling between climatic drivers of plant productivity and the response of ecosystems vegetation is required. We compared trends in six NDVI metrics (1982-2010) derived from the GIMMS3g dataset with modelled biomass productivity and assessed uncertainty in trend estimates. Annual total biomass weight (TBW) was calculated with the LINPAC model. Trends were determined using a simple linear regression, a Thiel-Sen medium slope and a piecewise regression (PWR) with two segments. Values of NDVI metrics were related to Net Primary Production (MODIS-NPP) and TBW per biome and land-use type. The simple linear and Thiel-Sen trends did not differ much whereas PWR increased the fraction of explained variation, depending on the NDVI metric considered. A positive trend in TBW indicating more favorable climatic conditions was found for 24% of pixels on land, and for 5% a negative trend. A decoupled trend, indicating positive TBW trends and monotonic negative or segmented and negative NDVI trends, was observed for 17-36% of all productive areas depending on the NDVI metric used. For only 1-2% of all pixels in productive areas, a diverging and greening trend was found despite a strong negative trend in TBW. The choice of NDVI metric used strongly affected outcomes on regional scales and differences in the fraction of explained variation in MODIS-NPP between biomes were large, and a combination of NDVI metrics is recommended for global studies. We have found an increasing difference between trends in climatic drivers and observed NDVI for large parts of the globe. Our findings suggest that future scenarios must consider impacts of constraints on plant growth such as extremes in weather and nutrient availability to predict changes in NPP and CO2 sequestration capacity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Biomass*
  • Carbon Dioxide / chemistry
  • Climate
  • Climate Change*
  • Conservation of Natural Resources*
  • Databases, Factual
  • Ecosystem
  • Humidity
  • Linear Models
  • Plant Development / physiology*
  • Rain
  • Seasons
  • Sunlight
  • Temperature
  • Time Factors
  • Weather

Substances

  • Carbon Dioxide

Grants and funding

The project is funded by the Dutch government and PBL- Netherlands Environmental Assessment Agency as an in kind contribution to the Rio Conventions. PBL is the national institute for strategic policy analysis in the fields of the environment, nature and spatial planning. It contributed to improving the quality of political and administrative decision-making by conducting outlook studies, analyses and evaluations in which an integrated approach is considered paramount. Policy relevance is the prime concern in all studies. PBL conduct solicited and unsolicited research that is always independent and scientifically sound. PBL is an autonomous research institute in the fields of the environment, nature and spatial planning. It is part of the Dutch Government organisation. The independence of PBL and its partner agencies CPB Netherlands Bureau for Economic Policy Analysis and the Netherlands Institute for Social Research (SCP) is safeguarded in the Protocol for the Policy Assessment Agencies, Staatscourant (government gazette) 3200, 21 February 2012.