On September 23 at the 2019 Climate Action Summit, young climate activist, Greta Thunberg, delivered an emotional speech calling out “baby-boomer bureaucrats ” as the cause for the looming climate crisis. She was met by enormous support from the younger generations, gaining over two hundred thousand likes and fifty thousand retweets on Twitter to date. Scrolling through Instagram on that fateful day in September, only reposts of Greta’s speech were visible. Thunberg now has 8.4 million followers on Instagram and she has garnered amazing support for her cause; however, retweeting her speech on an iPhone (the emitted energy of which ironically is equivalent to about 1.4 tons of CO2 annually) doesn’t really help save our planet. Thunberg’s speech was able to inspire a generation of younger people to fight climate change, but it is now time to actually do something about it.
Climate change is a very real problem. Mainstream scientists have calculated a 40% increase in atmospheric CO2 concentration just since 1950, and that the earth’s average surface temperature has risen about 0.9° C since the late 1800s. According to those scientists, the CO2 increase, and rise in temperature have devastating effects on our planet that include warming oceans, biodiversity destruction, melting glaciers (that otherwise store fresh water) and rising ocean levels, all of which contribute to record numbers of extreme weather events. Last year, the United Nation’s International Panel on Climate Change (the “IPCC”) issued a report by 90 scientists from 40 different countries that concluded if action is not taken to limit average global temperature from rising another 1.5° C by 2040, the consequences of global warming will be impossible to reverse. The upshot of the IPCC report is that if global temperatures continue to rise at the current rate, saving endangered species (such as cute, loveable panda bears) will be only one of our many problems. That report warns of droughts, hurricanes, fires, floods, and famines that will wreak havoc on mankind.
Thunberg’s speech and knowledge of basic middle school biology has led the uninformed masses to anoint “planting trees” as the savior of our planet. In April of 2019, TenTree, an Instagram account, created a post titled “Double-Tap to Plant a Tree” asserting that for every “like,” the organization would plant a tree. That post amassed more than 15 million likes, becoming the 4th most liked post on Instagram. In October of 2019, popular Youtuber MrBeast created an organization called #TeamTrees offering that for every dollar donated a tree would be planted. The #TeamTrees website has raised enough money to plant over 17 million trees. While it is difficult to document whether these organizations have or will actually plant the trees, there remain significant climate-change caused challenges to overcome regardless.
Through the process of photosynthesis, plants absorb CO2 from and release O2 into the atmosphere; however, a recent Columbia University study questions whether planting more trees will actually decrease CO2 levels in the atmosphere. According to the Columbia study, as climate change continues (with more common patterns of extreme weather, including more frequent and more severe droughts and rainy seasons) and the CO2 levels continue to rise, plants will actually start absorbing less CO2 because those environmental stressors inhibit photosynthesis.
As described at the end of Unit 3, environmental stressors such as increased temperature and lack of moisture can negatively affect photosynthesis. The researchers at Columbia tested whether increased rainy seasons and storms offset the effects of extreme droughts by running four different climate simulations and observing the effect of soil moisture on the rate of photosynthesis. During wet seasons, the plants were able to absorb more CO2 than under normal conditions, however, the increased absorption during rainy seasons did not equal the decreased absorption during dry seasons. In other words, droughts have a greater effect on photosynthesis than rain; as a result the extreme weather caused by global warming will likely cause plants to absorb less CO2 independent of how many more trees are planted.
Certain genetic modifications can make plants more resistant to dry seasons, and increase their rates of photosynthesis overall. In the case study “Stronger Plants” farmers used genetically modified strains of tomatoes to help plants survive and reproduce against the harsh stressors of a dry environment. The modification described in the case study allowed plants to produce more Glycine Betaine, a modified amino acid. More Glycine Betaine allowed plants to survive and reproduce during colder and hotter conditions than plants without the modification. CAM plants are another example of a genetic modification responding to environmental stressors. For typical C3 plants, during hot and dry conditions, plants close their stomata to prevent water from evaporating. However, by closing their stomata these plants limit the amount of CO2 they consume and simultaneously trigger a wasteful process called photorespiration in which no energy is produced. CAM plants however, have evolved to only open their stomata at night when the sun is not present to evaporate crucial water needed for photosynthesis, thereby allowing the plants to absorb CO2 at night, and to go through the Calvin Cycle (the chemical reactions that convert CO2 and other compounds into glucose) during the day. Both of these modifications to the process of photosynthesis allow plants to be more resistant to environmental stressors, and better able to survive and reproduce.
If global warming continues unabated and we do nothing to limit the planet’s temperature from rising 1.5° C in the next 20 years, it is predictable that glaciers will melt, sea levels will rise, and extreme weather will become commonplace. While planting trees certainly does more than ranting on the internet about how the baby boomers destroyed the planet, planting trees alone may not be enough to save humankind and this planet as we know it. Extreme environmental stressors clearly limit the effectiveness of that single strategy. In fact, with enough stress, trees planted now that have not been genetically modified might not even survive. However, by planting trees with genetic advantages these plants may be able to survive and even thrive despite the ferociousness of mother nature. In short, if we take our passion for saving the planet seriously, limit our waste, cut our fossil fuels, and use science instead of hysterics to our advantage, we just might stand a chance.