Note: This article wasn't intended to be a comprehensive history.
I graduated from high school shortly after the turn of the century (2003), at a time when there was heated discussion regarding global warming in society (e.g. Collins (2003), Murphy (2003)). Though, I now know global warming is more precisely termed climate change in scientific circles, as a high school graduate, I knew little about the issue. After all, none of my K-12 classes touched the subject. Few people from the scientific community had yet to enter the public debate, since most climate scientists work for universities or government institutions, and tended to publish papers rather than engage the public; meaning the general public was receiving climate change information from news outlets, think-tanks, or governments, rather than from scientists directly.
I attended community college right after high school, but didn’t get serious about college until the Great Recession. This was also around the time an inconvenient truth was released. This is typically where I say that I started attending college. Even after I began attending a state university, it was entirely possible that I could have avoided the subject of climate change all together. Many college students will never discuss the subject of climate change in an academic setting; and even more seem to avoid science courses all together. In fact, I only stumbled into the major (environmental science) that would formally introduce me to climate change about 2 years after attending college, and about 4 years after graduating from high school. The course was called earth systems science, and it just happened that the professor teaching the course was a climate scientist.
In earth systems science, you break the earth into distinct spheres (geosphere, hydrosphere, biosphere, atmosphere), and observe how each are interrelated. We covered each sphere in depth, but gave special focus to the atmosphere and climate change. Without getting into too much detail, it can be said that natural carbon flux between the three spheres is generally stable on an annual basis, and typically varies gradually over thousands of years. In fact, the last glacial period ended approximately 10 kyrs ago (Petit et al., 1999). However, the natural aspect to climate change was disrupted once humans began burning fossil fuels during the industrial revolution and beyond. After this point, carbon was being released from the geosphere at a rate greater than all spheres were cable of uptaking; this meant significant CO2 increases in the atmosphere. Though, it wasn’t until the early 1950s that atmospheric CO2 could be measured accurately, and even then, systematic measurements weren’t initiated until 1958 (Monroe, 2013).
The first atmospheric CO2 measurement in 1958 was 313 ppm (Monroe, 2013), with a corresponding temperature anomaly of 0.12°C (NOAA, 2015a). Just for background, the reference period for global temperature anomalies (departure from mean) is the average temperature of the 20th century (13.9°C) (NOAA, 2015b). When I took earth systems science in 2009, the average CO2 concentration was about 390 ppm (Tans and Keeling, 2015), with a corresponding temperature anomaly of 0.59°C (NOAA, 2015a). By the beginning of 2015, the average CO2 concentration was approaching 400 ppm (Tans and Keeling, 2015), with a corresponding temperature anomaly of 0.65°C (NOAA, 2015a). The Holocene exhibited relative temperature stability (Petit et al., 1999), under which, human civilization developed. If annual temperature anomalies continue to increase, our climate may depart (likely will) from the relative stability human civilization depends on.
Collins, S., 2003. Climate change issue heats up in Washington [WWW Document]. CNN. URL http://www.cnn.com/2003/TECH/science/07/25/hln.hot.earth.warming/ (accessed 1.22.15).
Monroe, R., 2013. The History of the Keeling Curve [WWW Document]. Keeling Curve. URL https://scripps.ucsd.edu/programs/keelingcurve/2013/04/03/the-history-of-the-keeling-curve/ (accessed 1.22.15).
Murphy, J., 2003. W. House Guts Global Warming Study [WWW Document]. CBS News. URL http://www.cbsnews.com/news/w-house-guts-global-warming-study/ (accessed 1.23.15).
NOAA, 2015a. Climate at a Glance [WWW Document]. Natl. Clim. Data Cent. URL http://www.ncdc.noaa.gov/cag/time-series/global/globe/land_ocean/ytd/12/1880-2014 (accessed 2.15.15).
NOAA, 2015b. Global Surface Temperature Anomalies – FAQ [WWW Document]. Glob. Surf. Temp. Anom. URL http://www.ncdc.noaa.gov/monitoring-references/faq/anomalies.php (accessed 2.9.15).
Petit, J., Jouzel, J., Raynaud, D., Barkov, N., Barnola, J., Basile, I., Bender, M., Chappellaz, J., Davis, M., Delaygue, G., Delmotte, M., Kotlyakov, V., Legrand, M., Lipenkov, V., Lorius, C., Pepin, L., Ritz, C., Saltzman, E., Stievenard, M., 1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399, 429–436.
Tans, P., Keeling, R., 2015. Trends in Atmospheric Carbon Dioxide [WWW Document]. ESRL Glob. Monit. Div. – Glob. Greenh. Gas Ref. Netw. URL http://www.esrl.noaa.gov/gmd/ccgg/trends/ (accessed 2.9.15).