The Mauna Loa Observatory (MLO) on Hawaii Island tests the concentration of carbon dioxide (CO2) in the atmosphere. In April and May of 2018, the MLO measured the highest concentration of CO2 ever recorded in human history. Four hundred ten parts per million (ppm). What does this mean for the world, the nation, and Fillmore County?
To be clear, water vapor is the world’s greatest greenhouse gas accounting for more than 95% of the greenhouse effect. This figure is often cited by the dwindling number of climate change deniers as proof positive that minor changes in CO2 levels are not to blame for the warming Earth. Why is most of the focus for slowing climate change about CO2? The answer lies with the nature of water and the fact that slightly more CO2 significantly increases evaporation, thus trapping more heat, triggering a positive feedback loop. More water vapor also increases the intensity of rain events.
Yet, the Earth has had huge CO2 fluctuations in the past without human intervention (since such events occurred before our species walked the planet), how do we know we’re causing it? Analyses from trapped air in ice core samples from Greenland and Antarctica provide geologists and climatologists a picture of prehistoric trends of CO2 emissions from 800,000 years ago. Similar studies involving carbon and oxygen isotopes in seashells also help shed light on atmospheric conditions millions of years ago. In short, the earth has not seen such high concentrations of CO2 for more than four million years. More importantly, the rate of CO2 emissions we see now is nearing those which occurred 66 million years ago that ultimately resulted in the extinction of the non-avian dinosaurs. Estimates of pre-industrial revolution CO2 levels are generally around 280 ppm (68% of where we are now).
Sixty-six million years was a long time ago; how will increasing CO2 levels affect the United States now? Disregarding the devastating affects from severe weather patterns, increasing CO2 will impact your wallet when it comes to many foods.
The oceans cover 70% of Earth’s surface and are natural CO2 sinks (meaning they absorb CO2). Studies clearly show a trend in ocean acidification directly resulting from additional CO2. Water that mixes with carbon dioxide forms carbonic acid, which can do wonderful things, like make pop fizzy or dissolve limestone to form caves, but it can also lower the pH levels of large bodies of water. This destroys sensitive calcium carbonate shells that protect many organisms in the oceanic food web. When the base of the web begins to collapse, it affects everything up the food chain, including humans. Oceans are a huge source of food for many people.
Fillmore County clearly doesn’t rely on seafood. What we rely on is agriculture, namely crop production. Unfortunately, increased CO2 in the atmosphere can also negatively affect crop quality. A study from 2016 highlights the misconception that rising CO2 levels should enhance crop production. Although this may be true in some crop varieties, the study clarifies that there is substantial evidence most vegetation, including many crop types, will see a decrease in productivity and nutrient value.
Earth has had more CO2 in the past, but conditions were different then. Humans weren’t around. CO2 emission rates are still increasing, and those of us alive now will not necessarily live long enough to see the full impact of our decisions.
What decisions do we make and what options do we have to ensure a good quality of life for our children and grandchildren? We can deny the impacts of CO2, we can ignore it, or we can talk about it and do something. What can we do if we want to change something but don’t know how? As always, we should collaborate, share ideas, and work together.
Sources and further reading online:
C4 photosynthesis in plants: https://www.britannica.com/science/photosynthesis/Carbon-fixation-in-C4-plants
Soil is a CO2 sink: https://www.nature.com/articles/nature17174
CO2 will hurt crop production: https://www.nasa.gov/feature/goddard/2016/nasa-study-rising-carbon-dioxide-levels-will-help-and-hurt-crops
Climate change and Crop Water Productivity https://www.nature.com/articles/nclimate2995
History of Earth’s CO2 https://www.esrl.noaa.gov/gmd/ccgg/trends/history.html
Carbon Cycle: https://www.pmel.noaa.gov/co2/story/Research
Crop Nutrient Depletion from higher CO2 levels: https://www.npr.org/sections/thesalt/2018/06/19/616098095/as-carbon-dioxide-levels-rise-major-crops-are-losing-nutrients
Ocean Acidification: https://www.pmel.noaa.gov/co2/story/Ocean+Acidification
Food nutrient depletion: https://www.politico.com/agenda/story/2017/09/13/food-nutrients-carbon-dioxide-000511
Changes in food composition data: https://www.ncbi.nlm.nih.gov/m/pubmed/15637215/
Sea-food consumption: https://www.ers.usda.gov/data-products/