trees
Carbon And North American Forests
Researchers have for the first time calculated the capacity of North American forests to sequester carbon. The detailed analysis by UC Santa Cruz and collaborators in China and Arizona considers two key factors: the natural process of forest growth and regeneration, and effects brought about by climate change.
Making Cities Cooler
Cities are particularly miserable during heatwaves. With lots of concrete and asphalt surfaces, they soak up lots of heat and re-radiate it. Lots of tall buildings block cooling breezes. Factor in car exhaust and heat from air conditioners and it all adds up to the urban heat island effect. Cities can be several degrees warmer during the day and as much as 20 degrees warmer at night. All of this extra heat is not just a comfort issue, it is a serious health problem.
Biomass: Renewable But Not Sustainable
Biomass is often touted as a green energy source. Just recently, the US Environmental Protection Agency declared biomass energy to be carbon neutral – a policy already embraced by many European countries. However, burning forests for fuel has hard limitations and ecological consequences.
Nitrogen In The Rocks
The carbon cycle is the biogeochemical process by which carbon is exchanged between the atmosphere, the terrestrial biosphere, the ocean, sediments, and the earth’s interior. Its balance is a key factor that influences the climate.
Tree-Planting Drones
One of the major causes of the increasing carbon dioxide levels in the atmosphere is deforestation. We chop down about 15 billion trees each year. Over time, our activities have reduced the number of trees on earth by about 50%. We do plant trees – these days, about 9 billion a year. It is a substantial number, but still leaves a net loss of 6 billion trees annually.
The Restoration Economy
Deforestation is one of the largest contributors to climate change. Forests cover about 30% of the world’s land area and are a crucial sink for carbon dioxide. Over time, we have been steadily reducing the amount of forest in the world to obtain wood and timber, open up farmland, build towns and cities, produce paper, make palm oil, and mine for minerals.
A Carbon Loophole
Many power plants in Europe and elsewhere are replacing coal with wood. For example, the Drax Power Station in Britain was its largest coal-burning plant and is now using wood pellets shipped from the southern U.S. in its boilers. According to the carbon accounting rules at the EU and elsewhere, the process is considered to be “carbon neutral.” But is it?
The idea is that new trees are being planted in the forests where the trees are cut to be burned in power plants. So, there is carbon neutrality. In principle.
European countries have embarked on a massive effort to switch to generating power from renewable energy. While there has indeed been major growth in wind and solar power in the 28 countries of the European Union, much of the new “green” power has come from burning wood in converted coal power stations.
A group of 200 scientists wrote to the EU last September insisting that bioenergy from forest biomass is not carbon neutral and that there must be tighter rules to protect forests and their carbon. Wood burning has become a loophole in controlling carbon emissions.
There are problems with the claims of carbon neutrality. There is no way to know whether enough new trees are actually being planted to replace those being burned. And then there is the time lag for tree replacement. Trees don’t grow overnight. There are also the carbon emissions associated with harvesting, processing and transporting wood.
There are most certainly ways in which burning biomass can be carbon neutral and can represent real progress over the use of fossil fuels. But caution must be taken to avoid exploiting loopholes in current climate rules that might actually result in increased carbon emissions.
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Carbon Loophole: Why Is Wood Burning Counted as Green Energy?
Photo, posted April 26, 2014, courtesy of Flickr.
‘A Carbon Loophole’ from Earth Wise is a production of WAMC Northeast Public Radio.
Removing CO2 With Plants
Plants are the world’s great storehouse of carbon dioxide. That is why deforestation is a major contributor to climate change. If only there were more trees and plants, more of the CO2 in the atmosphere would be absorbed and could no longer trap heat in the atmosphere.
The Spread Of Bark Beetles
Bark beetles are a global scourge of evergreen forests. Mountain pine beetles have destroyed pine trees across western North America. Spruce beetles decimated spruce trees from New Mexico into Colorado and beyond. Altogether, bark beetles have ravaged 85,000 square miles of forest in the western U.S, an area the size of Utah, since 2000. They have killed trees across an additional 65,000 square miles of British Columbian forests and have caused millions of dollars of damage to the lumber industry in states like Alabama and Mississippi.
Earthworms And Sugar Maple Decline
The decline of sugar maple trees has been observed for well over 50 years. It is not a specific disease or a syndrome but instead is a generalized set of symptoms that have been affecting these valuable trees in many areas for a long time.
Trees Are Not Enough
Trees are nature’s way of removing carbon dioxide from the atmosphere. Growing plants take up CO2 and store it in the form of their roots, stems and leaves. And in fact, a significant factor in the growing levels of carbon dioxide in the atmosphere has been the extensive deforestation that has gone on over the past couple of centuries.
Migrating Trees
The changing climate is having a marked effect on forests in this country. In particular, trees along the U.S. eastern seaboard are changing their range as they slowly seek to escape rising temperatures.
Carbon Dioxide Marches On
The end of 2013 marked the first occasional observations of carbon dioxide levels in the atmosphere of 400 parts per million. There is nothing magical about that value, but we do tend to focus on round numbers.
Liana Vines And Carbon
Liana vines are long-stemmed, woody vines that are rooted in the soil at ground level and use trees or other means of vertical support to climb up to the canopy to gain access to sunlight. There are numerous varieties from many plant families. And, for reasons that are not entirely clear, their abundance has doubled in recent decades.
Terrestrial Plants and Lake Ecosystems
Most of the planet’s freshwater stores are found in the northern hemisphere, a region that is changing rapidly in response to human activity and shifting climate trends. A recent study analyzed 147 northern lakes and found that many rely on nutrients from tree leaves, pine needles, and other land-grown plants to feed aquatic life.
Tires From Trees
Car tires are generally considered environmentally unfriendly because they are predominantly made from fossil fuels. Natural rubber is generally not used anymore; most tires are made from isoprene, which is chemically very like rubber but is produced by thermally breaking apart molecules in petroleum in a process called cracking. The isoprene is separated out and purified and then reacted to form the artificial rubber that is the major component in car tires. The tires eventually end up discarded in giant piles that represent one of our biggest waste disposal problems.
Dying California Trees
California’s trees are dying. According to the U.S. Forest Service, more than five years of drought in California has left 102 million dead trees across 7.7 million acres of forest. In fact, 62 million trees have died this year alone – a 100% increase from 2015.
The Zombieless Apocalypse
Post-apocalyptic fiction is all the rage these days. There are numerous stories featuring an endless list of civilization-ending disasters: asteroid collisions, cataclysmic earthquakes, nuclear wars, supervolcanoes, pandemics… the list goes on and on. Most of the time, humanity either perishes entirely, is reduced to a handful of heroic and astonishingly resourceful souls, or ends up inexplicably as zombies staggering around the landscape in search of brains.
Small Forests And Climate
Trees are the number one way in which carbon can be removed from the atmosphere and stored in vegetation over the long term. A single tree can absorb CO2 at a rate of 48 pounds per year. Because of this, the carbon footprints of 18 average Americans can be neutralized by one acre of hardwood trees. And it has been found that managed forests accumulate more carbon per acre than unmanaged forests.