BERLIN (AP) — A “climate guardian” satellite set for launching this weekend will greatly help scientists keep track of the rise in sea levels, one of the most daunting effects of global warming, a senior official at the European Space Agency said Friday. The satellite, known as Sentinel-6 Michael Freilich and jointly developed by Europe and the United States, contains cutting-edge instruments able to capture sea surface height with unprecedented accuracy, adding to space-based measurements going back almost 30 years. “This is an extremely important parameter for climate monitoring,” said Josef Aschbacher, the European Space Agency’s director of Earth observation. Billions of people living in coastal areas around the planet are at risk in the coming decades as melting polar ice and ocean expansion caused by warming push waters ever higher up the shore. “We know that sea level is rising,” Aschbacher said. The big question is, by how much, how quickly. Some studies estimate the world’s oceans will rise by at least 2 feet by the end of the century, hitting low-lying regions from Bangladesh to Florida. Aschbacher said measurements dating back to the 1990s show average sea levels rising first by about 0.12 inches per year, but in the past couple of years the annual rate was almost 0.2 inches.