The Eco Fair scheduled for Saturday on the grounds of East Hampton Town Hall, the town’s first-ever such event, will happen amid a steady drumbeat of dire predictions of climate-related threats to coastal communities, including sea level rise and more extreme weather. The town board is working toward a goal to derive the town’s energy needs from renewable sources and is among many municipalities and states acting to phase out the fossil-fuel emissions blamed for rising temperatures and associated impacts on the climate. The fair, from 11 a.m. to 3 p.m., is to include exhibitions by the town’s advisory committees, including the Energy Sustainability and Resiliency Committee, the Nature Preserve Committee, and the Litter and Recycling Committee, as well as groups such as Concerned Citizens of Montauk and the Surfrider Foundation and such initiatives as Energize East Hampton and South Fork Peak Savers. Energize East Hampton represents the town’s portfolio of energy technologies and approaches. It envisions a mix of energy sources like solar and offshore wind, battery storage of energy derived from those intermittent, renewable sources, and community choice aggregation. “We are rolling out community choice aggregation” at the fair, Linda James, the chairwoman of the Energy Sustainability and Resiliency Committee, said on Monday. Earlier this month, Ms. James was among those who urged the town board to aggressively pursue that strategy, as well as battery storage, to meet its goal to fully transition to renewable energy sources. The community choice aggregation model replaces the utility as the default supplier of electricity or natural gas, and gives municipalities an opportunity to find potentially better prices from private suppliers. It also allows municipalities to choose locally based renewable energy projects, such as solar, demand response, and microgrid projects, for their electricity supply. Such programs in seven states now serve more than five million customers.Ms. James and Frank Dalene, also of the Energy Sustainability and Resiliency Committee, told the board that it would have to hold a public hearing, adopt the enabling legislation, and promote its details to residents and businesses. Enabling legislation would not require the board to make a commitment until an aggregation program is developed, approved by the State Public Service Commission, and adopted. The South Fork Peak Savers Program offers free Nest thermostats to participants, rebates on energy-efficient swimming pool pumps, and free LED bulbs for commercial lighting, all aiding in lowering energy use at peak times.The committee, Ms. James said, is working closely with Lauren Steinberg, an environmental analyst in the town’s Natural Resources Department. “We’re very fortunate to have her,” she said. “She’s smart, she’s dedicated, she’s just the type of public servant you want to have in this position.” The recent momentum toward aggressive action comes amid an opposite thrust. Coral Davenport and Mark Landler wrote in The New York Times this week that after President Trump pulled the United States out of the Paris climate accord, rolled back environmental regulations, and repeatedly denied and mocked global warming, his administration is now trying to undermine the science on which climate policy rests. James Reilly, the director of the United States Geological Survey, has ordered that scientific assessments produced by his office will project the effect of climate change only through 2040, rather than through the end of the century, they reported. The goal, they say, is to present an incomplete and falsely optimistic picture of the impact of continued unchecked use of fossil fuels: The largest effects of current greenhouse-gas emissions will be felt after 2040. Also this month, the website Roll Call reported that Interior Secretary David Bernhardt told the Natural Resources Committee of the House of Representatives “that he hasn’t ‘lost any sleep’ over record levels of global emissions of climate-changing carbon emissions,” which this month reached 415 parts per million, “the highest carbon dioxide levels ever found in the atmosphere in recorded human history.” On the other hand, Axios reported this month that the federal Department of Energy’s 2020 budget request includes initiatives for energy storage technologies, which, it noted, “are critical to integrating more clean energy into every portion of the power grid.” Gov. Jay Inslee of Washington, who seeks the Democratic Party’s nomination to challenge President Trump next year, has made climate the centerpiece of his campaign. Another candidate, Senator Elizabeth Warren of Massachusetts, presented a plan this month that would require the Pentagon to reach net-zero carbon emissions on noncombat bases by 2030. And New York State’s Reforming the Energy Vision initiative aims to cut greenhouse gas emissions by 80 percent by 2050. In February, Representative Alexandria Ocasio-Cortez of New York’s 14th Congressional District and Senator Edward Markey of Massachusetts announced the Green New Deal, a nonbinding resolution calling for a sharp reduction in greenhouse gas emissions across the economy while delivering jobs in emerging clean-energy industries. Several candidates for president support a carbon tax, which many economists consider the most effective way to reduce greenhouse gas emissions. But efforts to price carbon have failed three times in Mr. Inslee’s state, most recently in November. Meanwhile, carbon emissions rose by an estimated 3.4 percent in the United States last year and by 2.7 percent globally. A carbon-fee-and-dividend scheme, which would assess a fee on all oil, gas, and coal used in the United States based on the greenhouse gas emissions they produce and return it to people as a monthly “carbon dividend,” remains the initiative on which Citizens Climate Lobby is “laser-focused,” said John Andrews of the group’s Long Island East chapter. The Energy Innovation and Carbon Dividend Act of 2019 now has 40 co-sponsors, he said on Tuesday. “I don’t know where it’s going longer term,” Mr. Andrews said, “but the idea is to keep pushing and hoping that there will be a tipping point where public opinion moves in the direction of ‘We need action.’ Oftentimes nothing seems to be happening, then there’s a shift in public opinion. You can’t predict that any more than when an avalanche is going to happen.”