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Mass: Sea level rise is not from climate change, so far

Seattle, and many Washington cities, rest along the shores of Puget Sound. (KIRO 7)

University of Washington Meteorologist Cliff Mass has run up against others warning about the effects of climate change. His most recent blog post will only continue that contention.

RELATED: How climate change will affect the Pacific Northwest

To be clear, Mass firmly promotes that the climate is changing and that human influence is a primary cause. He doesn’t agree on many points that others argue, however. For example, when many in Seattle said that climate change killed a tree, Mass was quick to point out that science doesn’t back that assertion. When some people pinned summer weather on climate change, Mass said otherwise.

In a recent blog post, Mass addresses sea level rise – another concern posed by climate change. He writes that the sea level rise measured in Seattle (with records going back to 1900) has been steady for more than 100 years – about 2.03 mm each year. But he points out:

The interesting thing is that the upward trend has been going on for a long time, well before the impacts of human emissions of greenhouse gases were significant. (The radiative impacts of increasingly CO2 became large in the 1970s and later). And rate of rise has been quite steady, with no hint of a recent acceleration. In fact, there has been minimal rise during the past 20 years.

Sea level is relative

Other communities, such as San Diego or Key West, have seen similar rises in sea level, but at different rates. This is because the water level is not the only factor at play. Mass points out that the land is not remaining at the same elevation. The ground is sinking in many regions. In the Olympic Mountains, Mass writes, the land is being pushed up. Measurements around the Olympics shows the sea level decreasing.

Mass concludes that the sea level rise over the past 100 years is primarily due to the end of a small ice age (between 1500 and the 1800s). The meteorologist, however, is not doubting that the sea level will be impacted by human-influenced climate change in the years to come.

On the other hand, our climate models suggest an accelerated rise of sea level rise due to greenhouse gas warming during this century … Extrapolating the current, steady upward trend implies about a .6 ft rise. If we include the impacts of greenhouse gas warming, there would be more. A National Academy of Sciences report did such an analysis suggesting a 4-56 inch increase by 2100, with a mean change of 30 inches (2.5 ft). But whether such model-driven estimates are reliable is uncertain: I suspect it will be on the high side considering the slow rise of the past few decades.

Read Mass’ entire blog post here.

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