A group of scientific organizations in the U.S. on Tuesday signed a joint letter to Congress, urging it to accept the reality of climate change and to take action. "Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research concludes that the greenhouse gases emitted by human activities are the primary driver," according to the letter from 31 organizations. "This conclusion is based on multiple independent lines of evidence and the vast body of peer-reviewed science," it said. The letter stresses that the effects of climate change are increasing daily and it appealed for greenhouse gas emissions to be substantially reduced in order to prevent additional effects to "extreme weather events, sea-level rise, and increased risk of regional water scarcity, heat waves, wildfires, and the disturbance of biological systems."The group offered to work with Congress on scientific issues while addressing the challenges of climate change.Organizations signing on to the letter include groups such as the American Association for the Advancement of Science, the American Meteorological Society and the Society for Industrial and Applied Mathematics. The letter reaffirms climate change concerns in a similar letter in 2009, which was signed by 18 leading scientific organizations. Senator Jim Inhofe is among more than 180 U.S. lawmakers who are climate deniers, according to some U.S. media reports.The senator has said the fight against climate change is actually about global control with little accountability, implying climate change is not a real threat.