|Fig. 1: This figure shows many of the world's leaders celebrating the signing of the Paris Climate Agreement in 2015. (Source: Wikimedia Commons)|
In 2016, nearly all the worlds countries historically agreed to sign the Paris Climate Accord, an international agreement aimed at curbing climate change through the reduction of CO2 and greenhouse gas emissions (Fig. 1). As part of the agreement, each country has set specific reduction goals, to improve the global response to climate change. Specifically, the main goal of the agreement is to keep the increase in global temperature to well below 2°C above pre-industrial levels, and ideally, keep it below 1.5°C. 
President Obama, while still in office, signed an executive order that allowed the United States to agree to join the agreement.  At the time, the only two countries that chose not to sign were Syria and Nicaragua. However, earlier this year, both Syria and Nicaragua finally agreed to sign, while President Trump promised to withdraw from the accord, sparking controversy.  This means that the United States will be the only country to not sign the agreement, leaving the US without any real plan in place to curb climate change. Various domestic and foreign leaders have expressed their dismay and concern, and many believe that the US withdrawal has the potential to be very dangerous and damaging.  In fact, roughly 70 percent of registered voters in the US believe the US should ratify the agreement, regardless of what other countries choose to do. 
The Paris Climate Accord is the first agreement that has been (nearly) universally accepted, indicating that world leaders are finally recognizing the dangers of climate change and are willing to take measures to do something about it. Global carbon dioxide levels are rising at a record pace, and last year reached an all-time high. Levels of carbon dioxide are now above 400 parts per million, while they were roughly 280 ppm before the Industrial Revolution.  Furthermore, global temperatures have risen nearly 2°C since the Industrial Revolution.  Thus, it is clear that something must be done to curb climate change.
Despite the widespread optimism and enthusiasm concerning the Paris Climate Agreement, many are quick to note that the goals may be unrealistic to achieve. Bjorn Lomborg, a prominent author and environmentalist, has noted that in order for temperatures to remain below 2°C relative to preindustrial levels, carbon dioxide emissions need to be reduced by roughly 6,000 billion tons. This is very impractical, considering that even if every single country meets its individual goal (which is unlikely, given that many countries never met their quota with the Kyoto Protocol), carbon dioxide emissions would decrease by only 56 billion tons. The problem would remain essentially unsolved.  Furthermore, various analyses have suggested that despite the efforts of the accord, global temperatures will still be around 3°C higher than preindustrial times by 2100, well above the goal of 2°C.  Even if all countries meet their quotas for the next 70 years, global temperature will be reduced by just 0.17°C by 2100.  Thus, perhaps the Paris Climate Accord isn't as beneficial for the environment as initially believed.
The Paris Climate Accord is a remarkable step in our fight against climate change. The entire world has come together in a common cause, and countries are finally taking climate change seriously. Although the agreement will likely have a negligible impact on curbing climate change, and there are many barriers ahead. it is certainly a great start.  In addition, it is possible that as renewables become cheaper and more efficient, we will figure out ways to give ourselves a better chance of accomplishing the goals outlines in the agreement.
© Ben Vierra. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 A. Simon-Lewis, "What Is the Paris Climate Agreement and Who Has Signed It?," Wired, 7 Nov 17.
 C. Mooney and J. Eilperin, "Obama's Rapid Move to Join the Paris Climate Agreement Could Tie Up the Next President," Washington Post, 11 Apr 16.
 M. D. Shear, "Trump Will Withdraw U.S. From Paris Climate Agreement," New York Times, 1 Jun 17.
 A. Leiserowitz et al., "Politics and Global Warming, November 2016," Yale Program on Climate Change Communication, 2016.
 S. Waldman, "Atmospheric Carbon Dioxide Hits Record Levels," Scientific American, 14 Mar 17.
 J. Eilperin, "World on Track For Nearly 11-Degree Temperature Rise, Energy Expert Says," Washington Post, 28 Nov 11.
 B. Lomborg, "The Charade of the Paris Treaty," The Wall Street Journal, 16 Jun 17.
 A. Vaughan, "Paris Climate Talks: What Difference Will Temperature Rises Really Make?," The Guardian, 4 Dec 15.
 B. Lomborg, "Impact of Current Climate Proposals," Global Policy 7, 109 (2016).
 L. Tarhuni, "Paris Climate Accord," Physics 240, Stanford University, Fall 2016.