The Social Democrat-Green Party coalition in Germany's federal government gave environmentalists a strong say in policymaking at the end of the twentieth century. As the twenty-first century begins, the Federal Environmental Agency in Berlin hopes to promote the efficient use of energy, to close substance cycles, and reverse land depletion trends, but the biggest problem comes from eastern industry. Lignite was the main source of energy in the former GDR, satisfying 70 percent of the east's requirement, leading to massive pollution throughout Germany. Lignite is still the principal domestic source of energy, with reserves reaching 43 billion tons in the Rhineland. The alternative, nuclear power, has gained ridicule from environmentalists who see nuclear power plants as more of a danger than a viable resource. A number of rivers and lakes flow in and around Berlin, which are as polluted as the streets of the city. The administration's energy policy hopes to reduce carbon dioxide emissions by 25 percent between 1990 and 2010, in part by building new, energy-efficient flats and limiting industrial pollutants. By 1995, carbon dioxide levels were down by ten percent. The Berlin Solar Campaign also hopes to bring solar energy, which can be used without creating harmful emissions, into widespread use. In recent years, flooding in Germany resulting from alternating El Niño and La Nina weather patterns and stimulated by global warming has washed away topsoil and endangered lives. It is hoped that with replanting and other soil conservation measures the land and forests will remain an important resource for generations to come.