Manufactured uncertainty over climate change, the fundamental strategy of climate change denial, has been very effective, particularly in the US. It has contributed to low levels of public concern and to government inaction worldwide.[1][215] An Angus Reid poll released in 2010 indicates that global warming skepticism in the United States, Canada, and the United Kingdom has been rising.[216][217] There may be multiple causes of this trend, including a focus on economic rather than environmental issues, and a negative perception of the United Nations and its role in discussing climate change.[218]