Satellites: Sea level rise to reach 2 feet by 2100

A new study in the Proceedings of the National Academy of Sciences confirms what global climate models have predicted. Melting ice sheets and Greenland and Antarctica combined with thermal expansion of warmer oceans is already pushing seas higher at a rate that will lead to at least 2 feet of sea level rise by 2100.

The study of satellite measurements shows the rate of sea level rise is accelerating over the past 25 years.

Seal level rise over the past 25 years. Image: University of Colorado-Boulder and Inside Climate News.

Here’s one take on the PNAS study from Inside Climate News.

The rate of sea level rise is accelerating so fast that some coastal communities could confront an additional 4 inches per decade by the end of the century—a growing concern now confirmed by thorough measurements from space.

At that rapid pace of change, vulnerable communities might not be able to keep up. Storm surges will increase erosion and damage homes, businesses and transportation infrastructure in some areas. In other places, seawater will intrude on freshwater aquifers. In South Asia and the islands, people will lose the land where they live and farm. And the changes will arrive much faster than they do today.

Scientists have been warning about this speed-up for many years based on computer climate simulations. A new study released Monday confirms the modeled trend with a detailed analysis of satellite observations spanning a quarter of a century.

The findings, published in the Proceedings of the National Academy of Sciences, reinforce the outlook that average global sea level is likely to go up at least 2 feet by the end of this century compared to 2005 levels.

The study confirms that the Intergovernmental Panel on Climate Change(IPCC), NASA and the European Environmental Agency were correct when they found that the rate of change had increased in recent years.

And if the rate of acceleration intensifies—as it might if global warming speeds the melting of the Greenland and Antarctic ice sheets and glaciers—a 2-foot rise might be the low end of the likely range. The study assumes a steady acceleration at only the rate observed in the past 25 years.

Storm surge flooding from Hurricane Sandy in Mantoloking, NJ. Image via New Jersey National Guard.

Higher “base state”

The faster rate of sea levels rise will likely overwhelm adaptation efforts in many coastal cities by the end of this century. The higher base state of oceans means storm surge-driven coastal floods will deliver more severe damage.

We tend to think of sea level rise as a slow-motion steady event. The reality is sea level rise can be uneven over time and space. Sudden surges can occur as climate change-driven glacial melt water pulses into our oceans from ice sheets in Greenland and other locations. More severe climate change-enhanced storms like Hurricane Harvey then drive more damaging storm surges further inland due to the higher ocean base state. The increase in flooding and damage can be exponential, not linear.

Bolivar Peninsula, TX, September 2008, after landfall of Hurricane Ike Image: NOAA:

It doesn’t take a genius to see that the current rate of sea level rise is highly problematic in this century. Simply extrapolating out current trends over time yields some very unsettling future scenarios.

Some of the most impactful and costly climate change events over the next 80 years will likely be driven by higher sea levels and storm surges. Forced mass human migration of millions of people are more likely to cause widespread unrest. Significant economic shock waves from catastrophic storm events are increasingly likely to stress test insurance markets and other economic systems. Significant sections of major cities like Miami will be permanently or frequently underwater by 2100. Trillions of dollars in real estate are at increased risk.

Climate scientists and even the U.S. national security community have been warning about the impacts of rising sea levels for years. What’s different about this week’s study is the measured satellite data of what’s already happening in our oceans. This is not some future model predicting what may happen. This is happening. Now.

Our oceans are rising faster than previously thought, and the pace is accelerating. Our atmosphere is warming and spawning more intense storms. My best assessment is we are just now at the beginning of an era of extreme climate change enhanced weather shocks like we saw last year with Hurricanes Harvey, Irma, and Maria.

This is the new normal.

  • Torquebolt

    Please concentrate on forecasting our local weather, and stop promulgating unfalsifiable theories and their accompanying catastrophic doomsday results. Thank you

    • Gordon near Two Harbors

      Trends and science matter. The US military is extremely concerned about sea level rise and climate change. This isn’t religion A, B, C, D…..

      • Torquebolt

        Who said religion? I am extremely suspicious of the numbers put forth in this paper, once again computer model based with fudged input, and I am currently researching it. I don’t take everything I read at face value. There has been record snow and cold in the Arctic. There are many, many opinions that refute the extrapolation of these measurements based on flawed input to the models. I suggest you do your own research, with an open mind as to what may be going on.
        Global warming (now Climate Change) is an infinitely flexible, unscientific, unfalsifiable theory which can be stretched to accommodate any observation. Some climate scientists even shamelessly reject the very concept of scientific falsification with regard to the conduct of climate science.
        I admit, I am a lowly citizen scientist. But I care deeply about the truth. If this brands me as a skeptic or denier, then so be it. I suggest you look through Climate Depot, or What’sUpWithThat concerning sea level rise, and fudging of numbers in models. Take care up north, Gordon. Bob in Osceola

        • Matt_Kuzma

          The study being discussed is not a computer model, it is actual measurement by satellite. The fact that you’re droning on about models tells me that your problem is with basic reading comprehension. That’s going to make your studies very challenging and it’s no wonder you’ve twisted yourself in knots trying to understand the science.

          • Torquebolt

            If you were to read the scientific paper, Matt, you would see that the “actual measurements” are put into a predictive model, there are “adjustments” made for tidal variations and satellite drift, and the program then crunches the numbers and spits out the prediction, if you think it doesn’t then you are the one droning on and tying yourself in knots, you arrogant little forkwad

          • Matt_Kuzma


            “Using the altimeter record coupled with careful consideration of interannual and decadal variability as well as potential instrument errors, we show that this rate is accelerating at 0.084 ± 0.025 mm/y2”

            Those are actual measurements of real data, not a simulation or a predictive model. They then use that data to calculate a trendline to project into the future.

            If you don’t believe in trendlines, it’s no wonder you have a hard time with science. The whole point of science is to make predictions, compare them to observations, and adjust your predictive models. That is what science is: a method of refining a predictive model. If simple predictive models are a deal-breaker for you, you simply don’t accept science as a source of truth. If you don’t accept science, why are you reading a site dedicated to whether predictions based on science?

    • Noelle

      Climate change has already been happening in front of our eyes, and I appreciate that Paul continues to report on this data. I disagree with your choice to continue doubting extensive scientific studies and the many, MANY scientific experts who are very concerned. Large businesses are already working on plans to mitigate risks that will arise due to climate change.

      • Torquebolt

        Well Gee Whiz, Noelle, I guess I should just accept the whole scam as Gospel truth then! BTW there are many, MANY more actual “scientists” who outright disagree with the whole “theory” but go ahead and spout your liberal talking points. No need to analyze anything, just take their word for it. Please read my other post below, in response to Gordon. Have a really nice day.

  • Matt_Kuzma

    Thank you for the important insights. Keep up the good work!

  • Roland

    Who deleted the dissenting comments?

    • 7cubed

      I deleted them, they were my comments, because I was being deluged by “climate change” fanatics. I attempted to explain some things, as a citizen scientist, not knowing that MPRnews is apparently a site full of Loons who believe in CAGW as Gospel. My points were valid, they were detailed, I was scoffed at like I am some sort of idiot. I enjoy the forecasting and graphics on this site, but I won’t be commenting here for awhile, because for all the time I have spent researching the topic, I really don’t appreciate being jumped on. But I will say this, they ain’t seen nothin’ yet. I am arming myself for BEAR next time. God Bless my home State of Minnesota.

      • Roland

        Thanks. Horror stories about climate change don’t scare me nearly as much as the thought of politicians trying to do something about it.

        • 7cubed

          Thanks to you also, Roland, and I concur. I am, even now, assembling a more forthright, precise and thorough series of remarks, complete with reference links that I shall submit to this thread by the end of February. I hope you will read them. My objective is truth and reason, common sense and zero BS. Good evening to you from Western Wisconsin.

          • Roland

            I look forward to it. When you do that, please also post a few words in reply to one of my comments here so I’ll get an email from Disqus.
            I find it odd when climate-change zealots harp about their critics not accepting “settled science.” I would be hard-pressed to come up with a more unscientific notion than “settled science.” Why are they so repulsed by dissent?
            The most important question we should always ask them is “Then what do you propose to do about it?” The worst scenario is a government plan based on research conducted by government-paid scientists. Would anybody believe Walmart if it said that its scientists predict a global calamity, and we must all pay Walmart to avert it?
            Any scheme that economically-illiterate politicians devise surely will involve nudging the population toward poverty through taxes and regulations that stifle wealth creation. If the predictions of hardship are valid, the last thing we should want is for people to be poorer and thus less able to cope.