The global warming debate, also known as the global warming controversy, is a long-running debate about the rise in global average air temperature since the mid-twentieth century. The cause and meaning of this observation are disputed by people on both sides of the global warming debate. For one thing, they can’t agree on whether the current warming trend is part of a millennia-old cycle of climatic variations or the result of increased greenhouse gas emissions caused by human activity. They also debate what the effects of global warming are likely to be, as well as what, if any, steps should be taken in response to global warming, with proposals ranging from drastic reductions in greenhouse gas emissions to doing nothing.
In the 1980s, Europe was concerned about global warming, or climate change, as it is more commonly referred to. Concern grew, and the UNFCCC responded in 1997 with the Kyoto Protocol, which aimed to stabilize greenhouse gas levels in the atmosphere in order to “prevent dangerous anthropogenic interference with the climate system.” The Kyoto Protocol was ratified by all European Union member states, but not by the United States, which merely signed it, a meaningless gesture. However, the United States was once an outlier.
At the end of the first decade of the twenty-first century, what had appeared to be a consensus that current climate change is caused by anthropogenic or human-made carbon emissions had eroded and renewed the global warming debate. According to reports, as of June 2009, over 700 scientists, including some who contributed to the report, disagreed with the United Nations climate summary created for policymakers in 2007. Other scientists who were not involved in the report but previously held the belief in human-caused global warming have also reversed their positions.
The renewed global warming debate could be due to a number of factors. One is that, since 2001, weather data has revealed rising carbon dioxide concentrations while temperatures have remained constant. This contradicts popular belief about the connection between carbon emissions and climate change. Another reason for this is that the economic downturn of 2008–2009 prompted a re-evaluation of scientific studies, as reducing carbon emissions would result in significant changes in industries, further harming the economy. Third, new peer-reviewed research has cast doubt on predictions about climate change’s expected effects, particularly on important issues like polar ice melting, rising oceans, and disease spread.