World-wide, thousands of people took part in the March for Science on Earth Day last Saturday. The Guardian‘s headline declared “Global ‘March for Science’ protests call for action on climate change” as the reason for the marches. Calls to action and defending scientists from attacks on the legitimacy of climate science, were the objectives.
First celebrated in 1970, Earth Day events are held to demonstrate support for environmental protection. The wider goals of this demonstration are laudable, but I have two ‘howevers’ around the March for Science action.
First is the irony of the marches – significant volumes of new carbon were emitted to the atmosphere from the vehicles used by participants.
Using the average emissions factor defined by our Environment Ministry for petrol vehicles and an average distance travelled of 25km, each participant released around 6kg of new carbon dioxide.
The second ‘however’ is that actions, not more words are now needed if global warming is to not exceed 2°C. That is the goal of the climate agreement that our government has committed to.
One of the few Earth Day events that actually achieved a reduction in atmospheric carbon dioxide (CO2) levels, was the Charcoal Fire event at St Andrews Anglican Church in Pukekohe last Sunday.
This event involved burning wood to make biochar. The char was buried, inoculated and two peach trees planted on top.
For each person attending that event, an estimated 3kg of carbon dioxide was removed from the atmosphere and buried away for a very long time. Plus the new trees will sequester more carbon for many years.
It may be that the Marches for Science had an impact on US politicians. It is clear that the Pukekohe event had an impact on reducing global warming.
How does the carbon cycle work?The carbon cycle is the movement of carbon between the atmosphere, oceans, soils, and plants.One part of that cycle involves trees and plants taking carbon dioxide (CO2) out of the atmosphere and converting it to carbon which becomes embedded within the tree, and to oxygen which is released back to the atmosphere.When a plant dies naturally, much of it’s carbon is released back to the atmosphere, and becomes available to other plants to absorb and continue the cycle.Soil contains one of nature’s largest stores of carbon which is slowly released to the atmosphere or locked away as fossil fuels.This balance in the carbon cycle has been a feature of our environment for millennia.We humans upset that balance when we add new carbon to the atmosphere by tilling the soil, extracting and burning fossil fuels, and when we cut down forests. We have been doing this for over 100 years, which is seen in the ‘hockey stick’ graph that charts rising atmospheric CO2 levels.