A news article appeared yesterday by Dyna Rochmyaningsih of SciDev.net which is part of the Guardian Environment Network titled
with further illustrates a continuing deficiency of the multi-decadal global climate models which have incorrectly been claimed to have regional and local predictive skill (e.g. see). Excerpts from the article are [highlight added]
Climate models should include the effects of trees on the local climate, say agroforestry experts
Current climate models and projections may be inaccurate because measurements are based on guidelines that do not include the effects of trees on the local climate, according to agroforestry experts.
This in turn may be hindering effective adaptation by local farming communities, as the true effect of climate change on their crops is not accurately captured.
Trees can influence many of the climate factors predicted by modelling, and their effects should be added to climate maps, scientists from the the World Agroforestry Centre (ICRAF) said in a book, How people and trees can co-adapt to climate change, launched last month (1 December)……
Following the guidelines of the World Meteorological Organization (WMO), global weather stations collect climate data on open ground — away from trees, said Meine Van Noordwijk, an editor of the book. The collected data are then used for climate modelling and projections.
But trees can affect the local climate in a region, for example by reducing the maximum temperature and increasing humidity, said Van Noordwijk. Depending on where the weather station is placed, with respect to the tree canopy, the data may be different and this might produce different results, he said.
“Unfortunately … climate scientists have not made much effort to quantify [the effects of trees]. By not looking at that, we are missing a large opportunity to understand how we can adapt.”
There is disagreement on their findings which is reported in the text
Rizaldi Boer, executive director of the Centre for Climate Risk and Opportunity Management in Southeast Asia and the Pacific, said that the logic behind the WMO standards was to avoid tree canopy effects on the measurements. Climatologists still include the effects of land coverage around the station in their models, he added.
Mr. Boer is not correct. While regional landscape information is inserted into the multi-decadal global model simulations, the models do not have the spatial resolution to “include the effects of land coverage around the station.”
Indeed, as shown in our paper
Fall, S., A. Watts, J. Nielsen-Gammon, E. Jones, D. Niyogi, J. Christy, and R.A. Pielke Sr., 2011: Analysis of the impacts of station exposure on the U.S. Historical Climatology Network temperatures and temperature trends. J. Geophys. Res., 116, D14120, doi:10.1029/2010JD015146.Copyright (2011) American Geophysical Union
the landscape in the immediate vicinity of a climate observing site very much matters. Moreover, the effect of local and regional landscape change as a climate forcing are still inadequately understood, as we discuss in
Pielke Sr., R.A., A. Pitman, D. Niyogi, R. Mahmood, C. McAlpine, F. Hossain, K. Goldewijk, U. Nair, R. Betts, S. Fall, M. Reichstein, P. Kabat, and N. de Noblet-Ducoudré, 2011: Land use/land cover changes and climate: Modeling analysis and observational evidence. WIREs Clim Change 2011. doi: 10.1002/wcc.144