evidence: "Current rates of acceleration mean that we are on track to add another 20 centimeters of global mean sea level by 2050, doubling the amount of change in the next three decades compared to the previous 100 years and increasing the frequency and impacts of floods across the world," said Nadya Vinogradova Shiffer, director for the NASA sea level change team and the ocean physics program in Washington. [...] Seasonal or periodic climate phenomena can affect global average sea level from year to year. But the underlying trend for more than three decades has been increasing ocean heights as a direct response to global warming due to the excessive heat trapped by greenhouse gases in Earth’s atmosphere.