Ocean winds blowing harder
The world’s oceans and ice caps are being transformed by climate change, posing greater threats to life and human society than scientists had realized, according to a special assessment of climate science focused on oceans and ice, released by the United Nations. The new report, from the Intergovernmental Panel on Climate Change, stresses that the watery parts of the planet are already entering a new state. Melt from the Antarctic is posing a greater threat this century than previously thought, and thawing permafrost is hounded by uncertainties over how much carbon it will release to the atmosphere, and how fast. The ocean is changing in structure and chemistry while heat waves increasingly strike its inhabitants. Although no amount of action now can stop some sea level rise, the worst of these effects can still be held off by cutting carbon emissions, the report says.
| By H. Jesse Smith |
May 10th, 2019 |
In this study, global satellite data were analyzed to determine trends in oceanic wind speed and significant wave height over the 33-year period from 1985 to 2018. The analysis uses an extensive database obtained from 31 satellite missions comprising three types of instruments—altimeters, radiometers, and scatterometers. The analysis shows small increases in mean wind speed and significant wave height over this period, with larger increases in extreme conditions (90th percentiles). The largest increases occur in the Southern Ocean. Confidence in the results is strengthened because the wind speed trends are confirmed by all three satellite systems. An extensive set of sensitivity analyses confirms that both the mean and 90th percentile trends are robust, with only small impacts caused by satellite calibration and sampling patterns.
