Global Warming Controversy

The global warming controversy concerns the debate over the existence of global warming, its causes and effects, and what (if any) actions should be taken. In the scientific literature, there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused primarily by human-induced emissions of greenhouse gases. No scientific body of national or international standing disagrees with this view, though a few organizations hold non-committal positions. Disputes over the key scientific facts of global warming are now more prevalent in the popular media than in the scientific literature, where such issues are treated as resolved, and more in the United States than globally.

Primary issues concerning the existence and cause of climate change include the reasons for the increase in global average air temperature, whether the warming trend is unprecedented or within normal climatic variations, whether humankind has contributed significantly to it, and whether the increase is wholly or partially an artifact of poor measurements. Scientists have resolved many of these questions decisively in favour of the view that the warming trend is unprecedented, that human activity is the primary cause and that it has been accurately measured. Additional disputes have concerned estimates of climate sensitivity, predictions of additional warming, and what the consequences of global warming will be. Although the primary issues are regarded in the scientific literature as settled, these additional disputes are still the subject of mainstream scientific debate.

Global warming remains an issue of widespread political debate, sometimes split along party political lines, especially in the United States. Many of the largely settled scientific issues, such as the human responsibility for global warming, remain the subject of politically motivated attempts to downplay, dismiss or deny them – a phenomenon widely known as climate change denial. The sources of funding for those involved with climate science – both supporting and opposing mainstream scientific positions – have been questioned by both sides. There are debates about the best policy responses to the science, their cost-effectiveness and their urgency. Climate scientists, especially in the US, have reported official and oil-industry pressure to censor or suppress their work and hide scientific data, with directives not to discuss the subject in public communications. Legal cases regarding global warming, its effects, and measures to reduce it, have reached American courts. The fossil fuels lobby, oil industry advocates and free market think tanks have often been accused of overtly or covertly supporting efforts to undermine or discredit the scientific consensus on global warming.