"As Americans observe Earth Day, Gallup finds 42% of Americans identifying themselves as environmentalists, down from an average of 76% in the late 1980s and early 1990s," the poll read.
Moreover, Gallup found that Americans are also less concerned about various environmental problems such as pollution of air, rivers, lakes and reservoirs and polluted drinking water, but are more concerned about issues like climate change than nearly three decades ago.
The results of the poll come as leaders from over 100 countries signed a UN agreement on climate change which aims to limit global average temperatures to less than two degrees Celsius above pre-industrial levels.
The UN deal also seeks to establish more financing for lowering greenhouse gas emissions and support more climate-resilient development.
Today, the US joined some 170 nations to sign the Paris Agreement — an historic step this Earth Day to protect the one planet we've got.— President Obama (@POTUS) 22 April 2016
In 1991, the same high percentage of Republicans and Democrats (78%) considered themselves environmentalists. Today, 27% of Republicans think of themselves that way, compared with 56% of Democrats, a partisan gap of 29 percentage points.
The decline in Americans' willingness to identify themselves as environmentalists is likely a result of many factors, including the politicization of environmental issues and the routine nature of recycling and other simple, environmentally friendly actions people might have once associated with environmentalism. Also, it is possibly because the term is less commonly used or may have taken on a different meaning than in the past.