There is no question that sea levels have been steadily rising, and will continue to rise at an increased rate in the future. So the real question is not, “Will it rise?” but, "How MUCH will it rise, and what can we do about it?”
The sea is rising. This, in itself, is not news. The oceans of Earth have been slowly, steadily rising for hundreds of years. But it’s about to get a lot higher a lot faster, and millions of people - and billions of dollars of infrastructure - are suddenly finding themselves at risk for flooding, storm surge damage, and possible relocation. How could something that has been a known factor surprise us, unprepared?
Meet Sea Level Rise, the new poster child for climate change. There is no question that sea levels have been steadily rising, and will continue to rise at an increased rate in the future. So the real question is not, “Will it rise?” but, "How MUCH will it rise, and what can we do about it?”
As we were just starting research for this story, I attended the SF Bay Decision Maker’s Conference on Sea Level Change.
There was one idea that permeated the entire day’s discussions:
- You can’t engineer for an unknown amount.
- Developers are aware of sea level rise, but do not know how to approach the issue. “Tell how much it will rise, and by when, and we can plan for it.”
Of course, it’s just not that straightforward. The science behind the estimates seems to be uncertain, providing ranges from as little as 12 inches by 2050, to as much as 80 inches by 2100. There is a consensus that the rate of sea level rise has increased in conjunction with the rise of global surface temperatures. The point of uncertainty is what the rate of sea level rise will be in the future. In 2007, German scientist Stefan Rahmstorf developed an empirical method for predicting future sea level rise using the relationship between sea level rise and global mean surface temperature. His estimates of global sea level rise by 2100 range from 10 inches (50 cm) to 55 inches (140 cm) respectively. Research estimates done for the Governor of California state that sea level will increase between 12 and 17 inches (30 and 45 cm) by 2050 and between 20 and 55 inches (50 and 140 cm) by 2099.
Most estimates show a wide range, depending on how much glaciers and ice caps melt over the next 90 years. The truth is that scientists don’t know how much other environmental factors will contribute to, or slow down, the rate of sea level rise. In addition, these are global estimates, which are averages and will not represent the exact numbers for specific locations. How much the sea level rises here in San Francisco Bay will not look the same as it will in Bangladesh.
The one thing scientists do agree on, however, is that sea level rise up to 2 meters (78 inches) is not out of the question, but certainly a high estimate. "Although increases of up to two metres this century can't be ruled out, this does not mean that they are inevitable or even likely."
And so we return to the question, “What should we do about it?” The truth is, we just aren’t sure yet. What we do know are the factors that contribute to the acceleration of sea level rise. Most scientists will tell you that, before we can fix the problem, we first need to stop the cause. Otherwise, we’ll never get ahead our heads (and our buildings!) above the water line.
Peter Gleick, President of the Pacific Institute in Oakland, tells us “the good news is that there’s a lot that we could if we’re smart enough to do it in advance. There are a lot of things that we could do to reduce the risks of climate change and sea level rise around the Bay. The first thing we need to do is reduce the severity of climate change. And that’s an issue of reducing greenhouse gas emissions, that’s got to be done at the national level. We’re doing a little bit of it at the California level. It needs to be done at the global level. But whether or not the politicians get their act together and reduce greenhouse gas emissions, we’re still going to have to deal with some sea level rise. That’s built into the gases we’ve already put into the atmosphere…But where we get to at the end of the century is going to depend on actions that California or the United States or ultimately the whole globe takes to reduce the rate of greenhouse gas emissions, to reduce the rate of climate change. If we don’t get our act together, if we don’t do things to reduce greenhouse gas emissions, we’re gonna reach a meter of sea level rise or more by the end of the century. And it’s gonna be growing even faster than it is now. But if for some reason we’re able to get a handle on emissions and the world is able to come together, we could slow that rate enormously, and limit the rate of sea level rise to hopefully only a few tens of centimeters. I don't think we’ll be that lucky, but that’s a possibility.”