These key ideas relate to the causes and effects of human-induced climate change. Show
Born on July 17, 1819, Eunice Newton Foote was the scientist who first published findings that CO2 traps heat. Her paper, "Circumstances Affecting the Heat of the Sun's Rays," was published in 1856. Foote's experiments with atmospheric gases and her insights about past climate were overlooked for more than a century. Drawing by Carlyn Iverson, NOAA Climate.gov. The potential for human activities to increase the temperature of the Earth through greenhouse gas emissions has been described and calculated for over a century. Volumes of scientific research across multiple scientific disciplines agree that humans are warming the climate, and the 2013 IPCC Fourth Assessment Report states, "Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system." (From the IPCC AR5) There is overwhelming evidence that human activities, especially burning fossil fuels, are leading to increased levels of carbon dioxide and other greenhouse gases in the atmosphere, which in turn amplify the natural greenhouse effect, causing the temperature of the Earth's atmosphere, ocean, and land surface to increase. That greenhouse gases "trap" infrared heat is well established through laboratory experiments going back to 1856 when Eunice Foote first measured the effect. The well-documented trend of increasing of CO2 in the atmosphere is caused by the burning of fossil fuels and massive land cover changes. The "smoking gun" that shows clearly that human activities are responsible for recent increases in carbon dioxide in the atmosphere is provided by carbon isotopes (carbon atoms of different atomic weight). These isotopes allow scientists to "fingerprint" the source of the carbon dioxide molecules, which reveal that the increased CO2 in the atmosphere is caused by fossil fuel burning (see references). The human causes of climate change are some of the most important concepts to teachDue to the basic physics of heat-trapping gases and an exponential rise in population and energy consumption, humans have become a force of nature. Clearly, this is a topic with enormous political, socio-economic and emotional dimensions, but the scientific results show clearly that:
Helping students understand these ideasDeforestation in Mexico. Credit: Jamie Dwyer The human impact on climate change is the most frequently misunderstood aspect of climate science. Some sectors of the public continue to debate whether these ideas can be true, despite the well-established science. There are several possible reasons why students may resist the conclusion that humans are altering the climate. This concept may be uncomfortable to students due to feelings of guilt, political resistance, or genuine lack of scientific understanding. Furthermore, projections of the effects of climate change on our society can frighten, overwhelm, or discourage students. This can result in denial or resistance to learning. Furthermore, even if a student possesses a firm grasp of this topic, it is nearly certain that at some point this knowledge will be challenged outside of class. Building a solid and careful scientific argument is essential. Educators are encouraged to introduce this topic with generous scaffolding that establishes the foundations of the process of science, the underlying principles of climate science, and a reliance on the robust scientific research that supports this conclusion. Several strategies are presented on this page about Teaching Controversial Environmental Issues which emphasizes the affective and emotional aspects of student learning. It may be tempting to have a debate about this topic, but that may not be the most effective way to characterize it. A debate suggests that there are two credible, opposing viewpoints, when in fact the scientific community is virtually unanimous about the human causes of climate change. Secondly, debating a topic can reinforce misconceptions and cause unnecessary controversy in the classroom. That said, careful discussion of diverse viewpoints is absolutely essential. Role playing can be one way to represent broad perspectives, while maintaining scientific accuracy. Bringing these ideas into your classroomCarbon emissions have risen from less than 5 billion tons per year in the late 1950s to over 36 billion tons per year as of 2019. This graph shows a breakdown of carbon emissions coming from each type of fuel, and much more information is available from the source: Our World in Data https://ourworldindata.org/emissions-by-fuel Even though this topic can be a sensitive one, it is also an essential facet to understanding climate change. Educators are urged not to shy away from the human role in shaping the climate, but instead to approach it in a deliberate manner, with pacing and framing intentionally designed to help your students understand the science and reconcile the meaning.
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What are 2 ways carbon dioxide increases in the atmosphere?Carbon dioxide is added to the atmosphere naturally by respiration (animals breathe in oxygen and exhale carbon dioxide), decay, and volcanoes. Combustion of fossil fuels, a human activity also adds CO2 to the atmosphere.
How have humans increased the concentration of carbon dioxide?Human Activity Is the Cause of Increased Greenhouse Gas Concentrations. Over the last century, burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO2). This increase happens because the coal or oil burning process combines carbon with oxygen in the air to make CO2.
What human activities produce the most carbon dioxide in the atmosphere?The main human activity that emits CO2 is the combustion of fossil fuels (coal, natural gas, and oil) for energy and transportation. Certain industrial processes and land-use changes also emit CO2.
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