Measuring Greenhouse Gases

From SCIANS

Measuring Greenhouse Gases (GHGs)

measuring Greenhouse Gases, closed chamber technique, gas chromatography, greenhouse gas emissions, GHG, global warming, climate change

What is GHG?

Greenhouse gases (GHGs) are gases present in our atmosphere that trap heat energy from the sun. This trapped heat raises the temperature of the earth’s surface just like a greenhouse. The gases accumulate from processes such as burning fossil fuels and certain industrial and agricultural practices.

What is global warming?

Refers to the most notable consequence of the greenhouse gas effect, which is the rise in the earth’s temperature.

What is climate change?

Climate change refers to the effects of the greenhouse gas effect. The increase in the earth’s temperature can cause dramatic changes in weather events. Climate systems may experience things like droughts, floods and frosts where they have never before. Local ecosystems become vulnerable to the harsh change in weather patterns coupled with rising sea levels, soil erosion and more.

The greenhouse gas effect

The greenhouse gas (GHG) effect warms the earth to a point that it can sustain life. The way it happens is gases in the atmosphere prevent the release of heat back to space by trapping it at the earth’s surface. High concentrations of these gases cause too much heat energy to be trapped; this leads to increased temperatures, global warming and climate change.

Climate change and agriculture

Climate change is a concern for all of us. It has particular importance to farmers because of its effect on temperature and weather conditions. The frequent, unpredictable and more extreme weather events caused by global warming make decisions regarding seeding dates, crop selection, pest and disease control, and irrigation a bigger challenge.

In the agriculture sector the 3 major greenhouse gases (GHGs) are:

Carbon dioxide (CO2)
Nitrous oxide (N2O)
Methane (CH4)

In Canada agriculture alone is responsible for 10% of all GHGs emitted.

6.1% as N2O
3.6% as CH4
≤ 0.1% as CO2

How do we measure GHGs?

To measure these GHGs we must first capture them. To do so we use a “closed chamber technique” because of its low cost and reliability. This method involves the use of a collar and chamber. The collar is a piece of PVC pipe 10cm tall with a 20cm diameter. This collar is inserted in the ground leaving a rim 2.5cm tall above the soil surface. The rim is what the chamber sits on. The chamber is an insulated and vented piece of PVC pipe that seals to the collar trapping emitted gases inside. Using a syringe we extract these gases from a sampling port at 0-minute, 10-minute, 20-minute and 30-minute intervals injecting each sample into a vial. The vials are taken to the lab and analyzed using gas chromatography. This analysis tells us the concentration of the 3 GHGs in each vial. From this we can determine the rate of gas accumulation in the chamber which can be related to the emission of GHGs from the soil surface.

Measuring Greenhouse Gases

From SCIANS

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