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Dr. Christian Reick

Global Vegetation Modelling Group Leader

Max Planck Institute for Meteorology, Hamburg

Phone: +49 40 41173-117

Climate Research . Ecology

Agriculture is plowing up the climate

Since the earliest beginnings of agriculture and livestock farming, humanity has been transforming areas of natural vegetation into cropland and pastures. However, the vegetation covering the continents influences our climate in a variety of ways.

February 15, 2010

Humans may well have been responsible for changes in the climate long before they started to burn oil and coal on a massive scale. Scientists at the Max Planck Institute for Meteorology in Hamburg have studied the spread of agriculture over the past millennium. Their research shows that humanity had a significant impact on climate, especially on the local level, even before the advent of industrialization.

Julia Pongratz, Christian Reick (Max Planck Institute for Meteorology)

Agriculture instead of forests. The natural vegetation in many parts of the world has been replaced by cropland and pastures. This has consequences for the climate. Zoom Image
Agriculture instead of forests. The natural vegetation in many parts of the world has been replaced by cropland and pastures. This has consequences for the climate. [less]

The study of church registers is an activity that is generally associated with theologians and genealogists rather than with natural scientists. Indeed, most people would find it very hard to imagine that such registers also contain important information for climate researchers. But these records, which go back many centuries, contain important information about population development and thus also about how much land area was used for agriculture. However, transforming natural vegetation into agricultural lands has consequences for the climate. We climate researchers are thus very fortunate that demographers have already done the work in recent decades and derived data on global population development from historical documents. Based on this data, we can deduce information about the human influence on climate many centuries into the past.

The pre-industrial era is particularly suitable for analyzing the consequences of land use on climate. Prior to 1850, the global expansion of agriculture was the only “manmade” disturbance to the global climate system. Since the expansion of agriculture often required the clearing of forests, the carbon stored in the wood eventually ended up in the atmosphere as part of carbon dioxide, a greenhouse gas. It was not until the mid-20th century that the amount of carbon dioxide that humans released into the atmosphere by burning fossil fuels significantly exceeded that caused by agricultural expansion. Since then, the global climate change that is now being observed has been caused largely by emissions arising from the combustion of coal, oil, and gas.

 

 
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