The global demand for reliable and affordable energy has led to an energy system that generates large amounts of carbon dioxide, primarily through the combustion of fossil fuels. In 2019, human energy-related systems emitted over 33.1 billion metric tons of carbon dioxide to the atmosphere that overwhelms the natural system balances of emissions and absorption (USGS n.d.a). The most recent reports by the Intergovernmental Panel on Climate Change provide a massive amount of detail regarding the measurements from independent lines of evidence like ice-core samples, atmospheric observations, and more that show the impacts of human activities on global warming and climate change (IPCC 2018). Nevertheless, there are many different interpretations of the data available, and many counterarguments have been made about the degree of impact humans have truly created. However, most of these arguments have been countered with deeper analysis.

Figure 1. Human Activities Impacting Climate

Source: (Cook 2010)

It is often stated by climate deniers that human emissions are small when compared to natural phenomena. However, this ignores the fact that those emissions and absorptions were balanced before human activities began negatively impacting that balance after the industrial revolution. Carbon dioxide isotopes that acidify oceans are directly tied to human activities and not natural ones (Cook 2010). Natural events have also impacted that balance and created temperatures rises historically as well, indicating that carbon dioxide levels are important to the temperature balance of the planet.

Figure 2. Carbon Dioxide Sources and Sinks Imbalance Due to Human Activities

Source: (Cook 2010).

When looking at natural events of the past, another common argument put forth is that emissions lag temperature in the historic record and that Milankovitch orbital cycles are the primary cause of temperature change, not emissions. Orbital cycles did initially trigger warming, however, more than 90% of the glacial-interglacial warming occurred after the atmospheric carbon dioxide increase as seen in figure 6 (Cook 2010). This indicates that carbon dioxide emissions are tied to rising global temperatures, and the isotopes analyzed show they are directly due to anthropogenic emissions.

Figure 5. Ice Core Samples from the Past 400,000 Years

Source: (Cook 2010).

Figure 6. Average Global Temperatures (Blue) Occur After Antarctic Temperatures (Red) and Atmospheric Carbon Dioxide Concentrations (Yellow)

Source: (Cook 2010).

Air Pollution Mitigation Assessment

While plans to reduce carbon emissions have been implemented in varying degrees worldwide, the overall progress and currently planned efforts are not sufficient to meeting this challenge. The Climate Action Tracker tracks nearly 80% of the global emissions that stem from 35 different countries. They analyze the current policies, pledges, and targets for each country to determine if they are on track in maintaining global temperatures below certain thresholds. Based on the most recent analysis, current policies would put the global temperature range increase between 2.1°C and 3.9°C by 2100, with updated pledges and targets only bringing the range down to 1.9°C to 3.0°C (Climate Action Tracker 2020). This indicates that not enough is being done to reach the goals of maintaining lower global temperature increases.

Figure 7. Climate Action Tracker Current Policies and Pledges Projections

Source: (Climate Action Tracker 2020).

Climate Change Impact Potentials

There are various signs that climate change is occurring due to these increased temperatures that include issues like droughts and tropical storms becoming longer and more extreme, reduced snowpack and glaciers, melting permafrost that releases methane, and sea-level rise and acidification. While threshold and tipping points for each of these elements can be difficult to predict and understand, it is clear that efforts to mitigate these issues is critical to avoiding even greater impacts. Some of the long-term effects that are expected based on current conditions are for 75 to 250 million people in Africa to be water stressed, with nearly 50% of rain-fed agriculture being reduced. In Asia, death rates and coastal destruction from floods and storms are expected to greatly increase. In Europe, flooding and erosion, as well as reduced snowpack will further reduce agriculture and tourism. In Latin and South America, a significant loss of biodiversity is expected that will also reduce tourism, agriculture, medicine, and water availability. In North America, decreasing snowpacks and drought intensification will lead to greater wildfire risks and desertification of agricultural land too (USGS n.d.b). These examples of projected issues will be costly from an economic, environmental, and social perspective so action to get human-induced global emissions in line with reduced warming goals should be the highest priority for governments, businesses, and citizens across the world.

Author: Logan Callen

References

Climate Action Tracker. 2020. “Countries.” Climate Action Tracker. Accessed August 8, 2021. https://climateactiontracker.org/countries/.

Cook, John. 2010. “The Scientific Guide to Global Warming Skepticism.” Skeptical Science. Accessed August 8, 2021. https://skepticalscience.com/docs/Guide_to_Skepticism.pdf.

IPCC. 2018. “Summary for Policymakers.” IPCC. Accessed August 8, 2021. https://www.ipcc.ch/sr15/chapter/spm/.

USGS. n.d.b. “What Are The Long-Term Effects of Climate Change?” USGS.gov. Accessed August 8, 2021. https://www.usgs.gov/faqs/what-are-long-term-effects-climate-change-1?qt-news_science_products=0#qt-news_science_products.

—. n.d.a. “What is the Difference Between Global Warming and Climate Change?” USGS.gov. Accessed August 8, 2021. https://www.usgs.gov/faqs/how-much-carbon-dioxide-does-united-states-and-world-emit-each-year-energy-sources?qt-news_science_products=0#qt-news_science_products.