Climate Crises: Yes, We Cause Them
“Human influence has warmed the climate at a rate that is unprecedented in at least the last 2000 years” (IPCC, 2021)
A climate agreement like the Paris Agreement that calls for limiting the increase of global average temperatures to 1.5° C addresses global warming. Observations show that since the 1950s, the average temperature of the atmosphere and oceans has increased, snow and ice have disappeared, and sea levels have risen (IPCC, 2014).
In 2014, the IPCC (Intergovernmental Panel on Climate Change) stated that the dominant cause of global warming is highly likely the increase in anthropogenic emission of greenhouse gases driven mainly by growth in economic activity and population. Still, the cause of global warming remained a topic of debate between believers and non-believers even though Cook et al. (2016) confirmed the scientific consensus of ninety-seven percent that humans cause global warming.
Despite such an overwhelming consensus, the then President of the United States of America, Donald Trump, announced in June 2017 that the US would withdraw from the Paris Agreement and stop its implementation (Jotzo et al., 2018). The US’ withdrawal from the Paris Agreement and, therefore, the loss of the nation’s share of envisioned global emission reductions amounts to twenty-five percent. However, the withdrawal will lead to higher emissions in the US due to endogenous adjustments — not imposing a carbon tax, which brings the total loss in global emission reduction to thirty-two percent (Larch and Wanner, 2019).
One of the first steps the current President Joe Biden took in January 2021 was to reenter the Paris Agreement and promise to tackle the climate emergency (Stracqualursi & Kann, 2021). Despite this, the US Energy Information Agency projects that energy-related emissions in the US will increase by five percent by 2050 compared to 2020 (EIA, 2021).
When in 2014, there was still some doubt, the latest IPCC report could not be more explicit.
Understand How Global Temperature Regulation Occurs
In matters of environment, unilateral decisions like the one taken by the Trump administration, or any unilateral decision to not reduce emissions or not reduce them fast enough, have a negative global impact. Yet, the decisions we make as individuals also have a global effect. To understand that impact, one must comprehend how global temperature regulation occurs.
The energy of the Sun heats the Earth. While the ground absorbs some of that energy, some energy reflects from the ground into the atmosphere, where greenhouse gasses or GHGs like CO2 (carbon dioxide), O3 (ozone), CH4 (methane), N2O (nitrous oxide), and H2O (water vapor) first absorb the energy and then re-emit it both upward and downward.
This natural mechanism — active throughout Earth’s history — further heats the ground and maintains the temperature in the atmosphere within certain limits and is called the greenhouse effect. While the greenhouse effect is a natural mechanism, human activity is accelerating the effect in the direction of warming up the Earth to the extent that it will have devastating consequences (McMichael et al., 2003).
Unlike water vapor, which condenses, both carbon dioxide and methane, for example, do not. CO2 is the historical and current number one GHG (CH4 is number two) responsible for global warming (high CO2) and cooling (low CO2), or, in other words, its concentration levels in the atmosphere control climate (Lacis et al., 2010). Never in the past eight hundred thousand years, a period during which carbon dioxide did not exceed three hundred parts per million (ppm), has one observed higher CO2 levels in the atmosphere than today, namely well over four hundred ppm (Ritchie and Roser, 2019). In July 2021, CO2 levels in the atmosphere reached 416.96 ppm (CO2.Earth, 2021).
Nevertheless, carbon dioxide is a crucial element of a planetary cycle that circulates carbon through four major reservoirs: the atmosphere, the terrestrial biosphere, oceans, and sediments (Post et al., 1990). Soil respiration or the emission of carbon dioxide from the soil and thus part of the carbon cycle significantly affects the total CO2 concentration in the atmosphere even when soil respiration changes slightly.
A unilateral decision that potentially increases CO2 concentration in the atmosphere, therefore, has a global impact. For instance, it took eight days for the smoke from wildfires in Australia to turn the skies in South America hazy (BBC News, 2020, webpage). Soon after, the smoke reached its source again after circling the globe (Roy, 2020).
The foundation of all life on Earth is a part of the carbon dioxide molecule, the carbon atom, or 6C, the fourth most abundant element in the universe (Riebeek, 2011). However, what keeps the living organisms that depend on oxygen alive is photosynthesis, a process powered by Sun energy that, through autotrophs such as plants, trees, and algae, produces oxygen and glucose from CO2 and H20 or water (Brenner, 2019).
Describing carbon and photosynthesis is essential to remember the vital fact — pun intended — that without oxygen, all breathing organisms and thus also all human beings die. The act of breathing originates in a human’s brainstem and is spontaneous, automatic, and regulated by a neural control system that depends on CO2 (Nattie, 1999). Too much carbon dioxide in the human body makes the blood acidic and can have toxic effects (Hernandez-Miranda and Birchmeier, 2015). Breathing in air containing more than one thousand particles per million or ppm can lead to headaches, vertigo, fatigue, concentration disorders, and smell disorders. Rates above two thousand ppm are hygienically unacceptable (Sevik et al., 2017).
On top of the fact that the US emitted more CO2 than any other country to date (Ritchie and Roser, 2019), the country’s decision to pull out of the Paris Agreement does have a global impact considering how nature regulates global temperatures through the carbon cycle. Despite the scientific consensus (Cook et al., 2016) that global warming since 1850 results from human activity, Harde (2019) argues the contrary; it is not anthropogenic or human activity, but rather natural processes that are the dominant cause of the increase in CO2 concentrations in the atmosphere.
Herndon (2018) points to air pollution due to coal fly ash, aerosols sprayed by jets to counteract greenhouse warming instead of greenhouse gases as the culprits of global warming. Such action would achieve the exact opposite of what it tries to achieve and “drive us ever-forward toward the first anthropogenic mass extinction of life on Earth” (Herndon, 2018, p.7).
Different opinions can exist, yet the overwhelming majority agrees that the increase in carbon dioxide is the leading cause of global warming. Although climate change deniers may persist, the IPCC’s 2021 verdict is crystal clear: “Human influence has warmed the climate at a rate that is unprecedented in at least the last two thousand years.”
The tiny killer in the atmosphere: PM2.5
Black carbon or the carbonaceous (rich in carbon) aerosol is possibly the second only to CO2 driver of global warming and conceivably responsible for more than thirty percent of recent warming in the Arctic (Center for Climate and Energy Solutions, 2010). Klimont et al. (2017) describe black carbon or BC as a species of PM or particulate matter, solid and liquid particles so small they remain airborne where they play a role in the climate system.
Compared to CO2, BC remains in the air for a short period, yet it contributes more to warming. What creates BC is the poor combustion of fossil fuels, biomass fuels, waste, coal and wood, in industrial and agricultural processes, transportation, and households, and natural vegetation fires (Gustafsson and Ramanathan, 2016).
There is a difference between primary particles, which are composites with a diameter smaller than 2.5 µm (PM2.5 or fine particles) or smaller than 0.1 µm (PM0.1 or ultrafine particles), and secondary or coarse particles with a diameter greater than 2.5 µm. Coarse particles have two distinctions; PM10 with a diameter smaller than 10 µm and Total Suspended Particle Matter or TSP up to 100 µm. Primary PM finds its way into the atmosphere while secondary PM forms in the atmosphere (Amaral et al., 2015).
The estimated annual number of premature deaths from exposure to ambient or outdoor PM2.5 in which BC — that penetrates deep in the lungs — is substantially present is three and a half million (Scrovonick, 2015). In 2021, the World Health Organization puts the number of premature deaths caused by PM2.5 at 4.2 million people (McGill, 2021); that’s 11,506 lives lost every day. And, it is only one example of the devastating impact of human influence on the planet. We must act now.
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