Keeping Old Forests Intact and Unfragmented Key to Minimizing Climate Change
It is becoming abundantly clear that ending industrial diminishment of primary and old growth forests [search] and working for their full protection and restoration is a keystone response to climate change (to say nothing of biodiversity and water crises). Over the past years ecological science has learned much regarding the importance of these ancient forests in regard to avoiding the worst climate change scenarios [search]. We have known for some time that these old forests are being lost at a rate of 13 million hectares a year, and many times more is permanently degraded through both first time selective “legal” and “illegal” logging. Last year scientific findings showed that contrary to conventional thought, intact old forests continue to act as a major sink for new carbon.
A recent Nature paper quantifies this, finding that 20% of industrial emissions are ending up in old tropical forests. We learned last year that when old forests are industrially logged for the first time they lose at least 40% of their carbon immediately, and are unlikely to ever fully recover their carbon holding potential. Untouched forests were found to hold 60% more carbon than replacement plantations. Selective logging causes habitat fragmentation, which opens up the canopy, leading to dryness and fire, and thus total loss of species and carbon. And a new study this week further clarified that due to fragmentation, climate changes and droughts, this carbon sequestration by old forests is gravely threatened [ark] — with the Amazon having become a source of carbon during the drought in 2005.
Keeping old forests' stored carbon in place, continuing new carbon sequestration, and keeping these ancient forests from burning and becoming a massive carbon source is best served by avoiding fragmentation associated with selective logging. By finding a way to fully protect old forests, you keep the long-time-stored carbon that would be released out of the atmosphere (about 20% of emissions) AND you remove 20% of the remaining 80% from fossil fuels. You avoid the 40% immediate loss from logging, and greatly decrease the probability of full carbon loss from fires. That is a net swing of at least 35% of anthropocentric carbon being kept or removed from the atmosphere by protecting and restoring old forests. This would appear to be second only to ending use of coal as a one shot action to address climate change.