June 2, 2017

Yesterday, June 1, United States President Donald Trump announced that the United States would formally withdraw from the Paris Agreement, an international treaty designed to combat global warming. The decision to withdraw from the treaty represented a sharp break with leaders of nearly all nations and went against the wishes of thousands of corporate executives, economists, environmentalists, other U.S. politicians, scientists, and even members of the president’s own Cabinet. Trump’s decision to withdraw from the treaty met with immediate international and domestic scorn and spurred numerous protests.

On June 1, 2017, protesters gather outside the White House in Washington, D.C., moments after President Donald Trump announced that the United States would withdraw from the Paris Climate Agreement. Credit: Kellybdc (licensed under CC BY 2.0)

By joining the Paris Agreement in 2015 and ratifying it in 2016, the United States had voluntarily committed to cut back on the use of polluting fossil fuels, develop more green (environmentally friendly) technology, and raise funds to help poorer countries reduce their greenhouse gas emissions. Trump, who has previously called climate change a “hoax,” sees these commitments as an unfair economic burden on the United States. Most evidence, however, shows that climate change is real and that moving to green technology actually stimulates economic growth.

The goal of the Paris Agreement is to slow and eventually cease the rise in global temperatures that has sharply increased in the last few decades. Scientists predict that, if global warming continues unchecked, it will damage human society and the environment. For example, global warming could melt enough of the ice near Earth’s poles to raise sea levels, flooding many coastal cities. Global warming could lead to more widespread droughts. It could also raise the risk of extinction for many plant and animal species. Already, global warming has greatly reduced glaciers at the North and South poles, harmed the world’s coral reefs, and created ever more erratic and extreme weather patterns.

Withdrawing from the Paris Agreement is a lengthy process that will take until November 2020 to complete, leaving time for the United States to rejoin the treaty. A number of U.S. cities and states have already announced they will continue to comply with the provisions of the Paris Agreement whether the federal government does or not.

November 8, 2016

Yesterday, November 7, officials from around the world gathered in Marrakech, Morocco, for the 2016 United Nations (UN) Climate Change Conference, or COP22. COP22 is an acronym for the 22nd annual session of the Conference of the Parties. The meetings come on the heels of the Friday, November 4, entry into force of COP21’s Paris Climate Agreement. One hundred countries—including the two considered to be the greatest polluters, China and the United States—have ratified the agreement for nations to report their greenhouse gas emissions.

UN Secretary General Ban Ki-moon (second left); Christiana Figueres (left), executive secretary of the UN Framework Convention on Climate Change; Laurent Fabius (second right), minister for foreign affairs of France and president of the UN Climate Change Conference in Paris (COP21); and French President François Hollande (right) celebrate the signing of the historic Paris Climate Agreement in April 2016. The agreement went into effect on Nov. 4, 2016. Credit: © Mark Garten, UN Photo

Most scientists believe that greenhouse gas emissions contribute to global warming. Global warming is an increase in the average temperature at Earth’s surface, specifically the warming observed since the mid-1800’s. If it continues unchecked, it may melt ice on land near Earth’s poles, raising sea levels; lead to widespread droughts; and cause certain plant and animal species to become extinct. Natural processes have caused Earth’s climate to change in the distant past. But scientists have found strong evidence that human activities have caused most of the warming since the mid-1900’s. These activities include the release of such greenhouse gases as carbon dioxide into the atmosphere, where the gases trap heat like a blanket around Earth.

Countries that have ratified the Paris Climate Agreement must assess and report their emissions levels every five years. However, they are not obligated to lower emission levels. Officials hope that such “name and shame” practices will encourage countries to do their best to reduce emissions. Now that the agreement has entered into force, the Marrakech conference is being called the “COP of Action.” Talk has shifted from finger-pointing and negotiation to working out action plans to slash greenhouse gas emissions.

In some cases, action plans have already been developed. A few weeks ago, in the African country of Rwanda, officials agreed to phase out the production of hydrofluorocarbons (HFC’s). HFC’s are a type of molecule used as a refrigerant in air conditioning and refrigeration systems. They were originally designed as a replacement for chlorofluorocarbons (CFC’s), which were found to damage the Earth’s protective ozone layer. Unfortunately, HFC’s were later discovered to be incredibly potent greenhouse gases, up to 12,000 times more powerful than carbon dioxide. Scientists estimate that the phase-out will prevent 0.9 °F (0.5 °C) of warming during the next century alone. Also last month, aviation industry officials met in Montreal, Canada, and agreed to cap the emissions of greenhouse gases on international flights.  The pact is not as strict as many scientists had hoped, and will only take effect in 2021. Nevertheless, it serves as a first step in controlling the greenhouse gas output of an industry that has largely resisted regulation.

April 28, 2016

Last Friday, April 22—Earth Day—representatives from 175 countries signed the Paris Agreement at the United Nations headquarters in New York City. The agreement stated that each country would voluntarily monitor and reduce greenhouse gas emissions. This agreement, which was developed in Paris, France, at the end of 2015, will be the most comprehensive climate change treaty ever—should it enter into force.

People gather for a climate change protest in front of the U.S. Capitol in Washington, D.C.
Credit: © Hyungwon Kang, Reuters/Landov

Global warming is an increase in the average temperature at Earth’s surface, usually used to refer specifically to the warming observed since the mid-1800’s. Much of the warming that has occurred is due to a process called the greenhouse effect. In the greenhouse effect, certain gases in the atmosphere, such as carbon dioxide, trap heat from the sun. They act much like the glass roof and walls of a greenhouse. Since the mid-1800’s humans have been releasing more carbon dioxide and other greenhouse gases into the atmosphere, mainly though the burning of fossil fuels. Scientists think these extra greenhouse gases are strengthening the greenhouse effect and causing the climate to warm. If it continues, global warming could cause extreme weather, flooding of coastal regions, and massive environmental changes.

The signing ceremony set a record for most signatures on a UN treaty on a single day. Signing the treaty is only the first step toward it becoming binding, however. State governments must now ratify the treaty, a processes that could take years. The treaty will go into effect once at least 55 countries that together produce at least 55% of global carbon emissions ratify it.

Even if the treaty is ratified, it will be up to individual nations to lower their greenhouse gas emissions. The treaty will require countries to assess and report their emissions levels every five years, but what they do with that information will be up to them. Climate change activists are hoping that the process encourages the countries to significantly curb their emissions. They hope the Paris Agreement will help keep global temperatures below 3.6 °F (2 °C) higher than their averages in the 1800’s. Scientists think that some of the most harmful effects of climate change can be prevented this way.