Land use can influence climate more than greenhouse gases
WUWT reader T.G. Brown writes:
My monthly copy of Physics Today arrived today with a cover story on ‘Land Use and Climate Change’, co-authored by Roger Pielke Sr., Rezaul Mahmoud, and Clive McAlpine. While it is largely preaching to a warmest crowd, the message is compelling: …even if global average temperatures were contained, human impacts on climate would manifest in other potentially dangerous ways. . Piehlke et. al. are talking specifically about land use: deforestation, various farming practices, etc.
Toward the end of the introduction, there is a compelling quote by Gordan Bonan (NCAR) NASA Earth Observatory: Nobody experiences the effect of a half a degree increase in global mean temperature … land cover change is as big an influence on regional and local climate and weather as doubled atmospheric carbon dioxide–perhaps even bigger.
It’s a nice article, and available here: http://scitation.aip.org/content/aip/magazine/physicstoday/article/69/11/10.1063/PT.3.3364
Land’s complex role in climate change
To date, most reporting on climate has focused on the possibility of catastrophic warming due to carbon dioxide and other greenhouse gases released into the atmosphere. The assessment of climate change risk has essentially been distilled to a single metric: the global average surface temperature. That reality was evident at the 2015 United Nations Climate Change Conference in Paris, where the central negotiating point was whether the global temperature rise should be limited to 1.5 °C or 2 °C. Indeed, a 2016 opinion piece by Simon Lewis (University College London and the University of Leeds, UK) states that, “by endorsing a limit of 1.5 °C, the [Paris] climate negotiations have effectively defined what society considers dangerous.”1
But the reality of humans’ impact on climate is exceedingly complex.2 Even if greenhouse gas emissions could be eliminated completely, other harmful anthropogenic sources of climate change would remain. And even if global average temperatures were contained, human impacts on climate would manifest in other potentially dangerous ways.
One often overlooked human factor is land use. Deforestation, dryland farming, irrigated agriculture, overgrazing, and other alterations to the natural landscape can disrupt Earth’s natural balances and change weather patterns. As with the addition of CO2 into the atmosphere, the effects can last for decades or longer and affect regions distant from the original offense. Given continued rapid population growth, they threaten to be irreversible.
The article: Download PDF