Monday, August 26, 2013

Burning wood is not a simply carbon neutral exchange

There are plans in Europe to run powerplants on burning wood to make electricity.   The current rules for carbon neutrality allows this to be considered neutral as an activity but I disagree with that as an approach.

Whenever wood is burnt we dramatically speed the process at which the stored carbon is released.   If do not burn wood it takes much longer for the wood to decay and release the carbon.   The average time for a the carbon in a 100 year old tree to be stored is 50 years or so, if you burn it is released right away.

A 2x4 that is used for construction of building is likely to remain in place in that building for 50 years.  Once the building is no longer needed the 2x4 is most likely going to end up in a landfill, though burning demolition waste is becoming more common.   If the 2x4 does end up in the landfill it can decades longer before it decomposes.    Realistically a 2x4 will store carbon for 80 or so years.    This means in a 100 year old tree that is harvested the carbon will be stored for an average of 130 years which is 2.6 times as long as if you burn the wood.

The burning of wood significantly speeds up the carbon cycle.   One has to remember that the trees cut down have not grown to the end of their natural life and the decay process in the forests is not a fast one.   Finding 100 year old remains of trees in the forest is not uncommon.   All timber harvesting speeds up the carbon cycle, burning harvested trees shortens it even more so.  It is only an old growth forest that is truly carbon neutral.

In either case there is carbon being emitted which adds to the load already in the atmosphere and oceans.  While the very fact that wood is part of the carbon cycle and is not a fossil fuel means it is an improvement over even the best fossil fuels it is still not neutral with respect to carbon emissions.

Tuesday, August 6, 2013

People Confuse Weather and Climate

As humans we do not live long enough to be able to really notice changes in climate.  To notice the change that is going people need to have lived in the same spot for half a century as an adult and paid attention to the natural world.   Very, very few people have done this or are capable of doing this.   People see individual weather events as an indication of a climate change.

I am almost 48 years old but I do not honestly remember if there has been changes to weather from the 1960s or 70s because I was not old enough to really know the climate.   Since I have been an adult I have lived the longest in the Lillooet region, 9 years and Victoria for 9 years, neither of these are long enough for me to see the trends on an observational level.

Weather is what happens every day and we remember the extremes we experienced within our life.  Climate is the context within which the weather happens.  Climate is the long term reflection of the norm, it is an average of what happens which means you need a long data series to know what normal is and to know if there is change happening.  

To understand climate we need hundreds of years of data and know how all the data is affected by local changes because of human civilization..A ten or twenty year data set tells us very little unless we can compare it to the past.  What we as people remember is the weather, the anomalies over the short term.

Someone that has lived in the same rural location for 50 or more years and had to pay attention to the climate might be able to know enough to see a change.   Are plants sprouting earlier?  Is it wetter or drier?  Is there a longer frost free period?

I love the fact that for Victoria we know have close to eight years of weather data for a multitude of locations across the city.   But this data does not tell me if there is a change in climate.  I am beginning to be able to see patterns in microclimates in Victoria and even close to where I live, but it is not enough to know what is really normal and what is not.   I have better information on the frost free period but not enough to be certain it may not come late in the spring or early in the fall.    I also do not have five decades of personal experience in this neighbourhood.

We need a lot more detailed microclimate data to know what may be happening but it will be hard to recreate the data from decades or even centuries ago with enough precision needed to matter.