Global Warming It’s the Trees’ Fault

Looks like Ronald Reagan’s statement may not have been so wrong when he said: “Trees cause more pollution than automobiles do.” — Ronald Reagan, 1981

The assumption that planting new forests helps limit climate change has been challenged by a new study.  Researchers found that in Europe, trees grown since 1750 have actually increased global warming.  The scientists believe that replacing broadleaved species with conifers is a key reason for the negative climate impact.  Conifers like pines and spruce are generally darker and absorb more heat than species such as oak and birch.  The authors believe the work has implications for current efforts to limit rising temperatures through mass tree planting.

The research team reconstructed 250 years of forest management history in Europe – and found that the way forests are controlled by humans can lead to far less carbon being stored than would have been the case when nature was in charge.  Removing trees in an organised fashion tends to release carbon that would otherwise remain stored in forest litter, dead wood and soil.  Choosing conifers over broadleaved varieties also had significant impacts on the albedo – the amount of solar radiation reflected back into space.  “Even well managed forests today store less carbon than their natural counterparts in 1750,” said Dr Kim Naudts who carried out the study while at the Laboratory of Climate Science and Environment in Gif-sur-Yvette, France.

Speaking to Science in Action on the BBC World Service, she said: “Due to the shift to conifer species, there was a warming over Europe of almost 0.12 degrees and that is caused because the conifers are darker and absorb more solar radiation.”  The researchers say that the increase in temperature equates to 6% of the global warming attributed to the burning of fossil fuels. They say that is a significant amount and believe that similar impacts are likely in regions where the same type of afforestation has taken place.  Many governments have made planting trees a key part of their plans for dealing with climate change; China is building a “great green wall” of trees, set to cover around 400 million hectares when complete.  The authors suggest the world should look carefully at both the types trees that we are planting and the ways in which they are managed.

Trees’ Role in Global Warming

Leave a Reply

Your email address will not be published. Required fields are marked *