If Polar Ice Melts How Much Will Sea Level Rise?

Probably no single item brings the scientific-political argument over climate change more into focus than sea level rise and its consequences. Here are the facts to counter the “alternative facts” that have been floated in national political discourse. See also the earlier article (http://askageologist.blogspot.com/2013/07/climate-change-is-it-real.html) on “Climate Change – is it Real?” Curiously, only in America is the science of climate change being questioned. However, only in America (and Myanmar) do we still use feet, pounds, and gallons.

In all fairness, this is not an easy scientific problem to address. Non-linear behaviors (something changing much faster than the variable forcing it is changing), and extremely complex interlocking feedback between physics and chemistry related to Earth’s weather systems, makes any modeling truly daunting. Nevertheless, scientists have developed a number of predictive models, and they are beginning to agree ever more closely.

Q: What if all the ice caps melt how bad will it flood the nearby continents, and would it change the tides of the world? How fast would the world have to react.

– Stephen L

A: There are about 21 million cubic kilometers (5 million cubic miles) of ice on the Earth’s surface. If all of this melted, it would raise sea levels by about 65 meters (215 feet). An image compiled by National Geographic magazine (http://www.nationalgeographic.com/magazine/2013/09/rising-seas-ice-melt-new-shoreline-maps/) gives a breath-taking sense of what this would mean for humanity. Florida would disappear – Washington, DC, also. This isn’t going to happen immediately, of course. For all this ice to melt would require the average global temperature to rise from a current 14C (58F) to 27C (80F). This is not impossible, especially if carbon continues to be extracted and burned at current rates or higher. 

However, there are many issues beyond polar ice involved with sea level rise:

  1. Tectonic changes
  1. Thermal expansion of the oceans
  1. Melting ice
  1. Local weather events (e.g., hurricanes)
  1. Ocean albedo change
  1. Methane clathrates
  1. How fast will it rise?
  1. Tectonic changes are an issue because, all things being equal, sea level is an equilibrium by definition and should rise everywhere at the same rate. Nevertheless, the east coast of North America is seeing a greater sea level rise than the west coast. This is because of tectonic changes, related to mid-Atlantic sea floor spreading, that are causing steady (tectonic) sinking along the east coast of the United States.
  1. Thermal expansion is important because if you heat water it will expand. With climate change well underway (and isotopic studies indicate that it is largely man-made), we can expect all the world’s oceans to expand… and therefore rise. Water is at its most dense at 4 degrees Celsius. Freeze water and it will expand (this explains why frozen water pipes burst). Warm it above 4 degrees Celsius and it will also steadily expand.
  1. Antarctica is covered with ice an average of 2,100 meters (7,000 feet) thick. If all of the Antarctic ice melted, sea levels around the world would rise about 60 meters (200 feet). Arctic ice is not nearly as thick, but Greenland by itself, if all its ice melted, would increase sea level rise an additional 7 meters (20 feet).
  1. Local weather events are the most immediately attention-getting, and there are at least two different aspects to this. Warmer ocean water translates into more heat energy going into a hurricane – the storms become bigger and the destructive wind velocities become stronger. The recent Atlantic hurricane Irma is a case in point: it is the largest and strongest Atlantic hurricane ever recorded since measurements were first acquired. When its eye reached the southern tip of the Florida peninsula, it’s outer rain bands were already into Georgia – and that was just half of this monster. However, hurricanes push seawater before them and drag at their cores a huge low-pressure zone, and these give rise to what is called a “storm surge.” The storm surge for hurricane Katrina, which devastated New Orleans in 2005, caused over US$100 Billion in damage largely because its storm-surge was an additional 5 meters (16 feet) above the normal tidal differences. Add a “king tide” (when Earth, Sun, and Moon are aligned and the high tide is greatest) to a 5 meter storm surge and you have a very destructive combination. It’s like a giant, slow tsunami.
  1. If ice disappears from the poles and from Greenland, then the albedo of the Earth will change. Albedo is the percentage of the incident light or radiation that is reflected by a surface, and is typically used for a planet or moon (the Moon’s albedo is about 20%, which means about 20% of sunlight is reflected and 80% is absorbed). In this case, ice-covered polar regions are very strong (though not perfect) reflectors of sunlight. If the ice were to disappear, the energy absorption of the polar regions would increase dramatically. Like ocean warming, this is another contributor to the non-linear character of sea level rise: a simple increase in a certain value causes secondary effects that dramatically increase the effect disproportionately in a non-linear fashion.
  1. Methane clathrates (a.k.a. methane hydrates, “fire ice”, etc.) are methane-ice held in a suspended quasi-stable crystal state found in the world’s cold deep ocean sediments (below at least 200 meters or 600 feet depth). This methane is a product of carbon being sequestered over time by CO2 capture (decayed materials falling to the ocean floor). The amount of carbon sequestered in this form beneath the world’s oceans is estimated between 500 and 2,500 gigatons, comparable with all known sources of hydrocarbons (oil and gas) found on land. There is evidence now that ocean temperatures as deep as 500 meters are rising. Methane, being a far stronger greenhouse gas than carbon dioxide, if released in these numbers, will cause a dramatic rise in global temperatures. This is another contributor to the non-linear character of sea level rise, and helps explain why estimating climate change consequences is so difficult.
  1. How fast will sea level rise happen? That is the million-dollar question for our age. The Intergovernmental Panel on Climate Change issued a report in 1995 containing various projections of the sea level change by the year 2100. They estimated that average sea levels worldwide will rise 50 centimeters (20 inches), and their +/- range went up to 95 centimeters (over 3 feet). The rise will come in part from thermal expansion of the ocean and in part from melting glaciers and ice sheets. Fifty centimeters is no small amount – this could have an enormous, disproportionate effect on coastal cities, especially during storms like Katrina, Sandy, or Irma. Keep in mind that this estimate is over 20 years old, and more recent sea level rise estimates vary widely but are not small. Since that 1995 report there have been gigantic ice sheet calving events in the Antarctic. The most recent (Summer of 2017) on the Ross Ice Shelf was an “iceberg” the size of Delaware, that ranges from 15 to 50 meters (up to 165 feet) high… and it will all melt as it drifts northward.  

About 80% of the human population now lives within 100 km of an ocean, and the most expensive and sought-after kinds of land are ocean-front properties. You don’t have to be a rocket scientist to realize that ocean-front property investment might not be a good idea. Miami “dodged the bullet” from hurricane Irma in September 2017, but it’s just a matter of time before a larger, even more destructive hurricane will hit it dead center. The loss of life and property to just Miami alone are unimaginable. The entire eastern United States is at risk, and hurricane Sandy (2012) made it clear that low-lying cities like Washington DC and New York are at terrible risk due to climate change. Giant typhoons in the subtropical Pacific are causing huge damage every year to east and southeast Asia, Japan, and the Philippines. 

We should be have been reacting to these scenarios long ago. Places like The Netherlands and the City of Venice have certainly been taking steps to mitigate the consequences of sea level rise for decades now. However, the world needs to address the reason for it. Choosing myth over climate science is not the way to go. That approach didn’t work for Big Tobacco, either.


An aside: recently, a US Congressman, who probably should not be named to avoid further embarrassing him, argued against the vast and accumulating evidence of climate change, saying that sea-level rise is cause by “…rocks …falling into the sea.” [https://www.huffingtonpost.com/entry/republican-congressman-explains-sea-level-rise-its-rocks-falling-into-the-sea_us_5afef746e4b07309e057985b]

He apparently doesn’t understand the difference between a bucket and an ocean. 


Risks of Working in a Rock Shop

 Q: Greetings,
     I work for a small business rock shop that carries a very large variety of gemstones and minerals. I have wondered for quite some time if I should be concerned about exposure so certain elements like lead, arsenic etc. We handle mostly everything without gloves or the use of dust masks.
I am now pregnant and even more concerned about this. I know that doctors and other professionals will advise the use of safety precautions regardless. My question is not that if we should use precautions, because I know that we should anyways. The question I am asking you, is if there is plausible serious risk through skin contact and inhalation? Do you know of any risks, are you able to provide specific examples of situations where problems have occurred /or might occur?
One example is of the handling of iron pyrite. It leaves behind black residue (we do use gloves for this) and creates a strong smell and dust in the air. Am I exposing myself to something serious here?
Also, I’ve heard of a new fad where the folks who believe in metaphysical properties of stones are putting them in their drinking water. I found this alarming.
I look forward to your response! Thank you for your time.
Thank You,
– Stacey S.
A: This is a VERY important query, and kudos to you for asking – and for your  determination to protect your unborn baby.
YES. There are minerals that are really dangerous: realgar and orpiment have mercury in them, for example. You can look up Minamata Syndrome to get an idea of how bad these could be to a fetus: https://en.wikipedia.org/wiki/Minamata_disease 
YES. There are various forms of asbestos that kill – literally. My father died a premature death from lung cancer. The biopsy showed that there was asbestos in his lungs, ultimately traced to dust in the basement of his apartment building in San Francisco where he kept his bicycle. The pipes had been insulated with spray-in asbestos in the 1950’s when the building was originally constructed. I’d be willing to bet that the workers who blew in that insulation preceded him.
POSSIBLY. Pyrite (FeS) is a mineral that will oxidize in the atmosphere. The bright shiny mineral faces will eventually dull and then go brown. The smell you describe is probably H2S, normally not toxic in small amounts (the smell warns us to get away – this is common around volcanoes I’ve worked in). My concern is that there are other sulfides that are often naturally associated closely with the pyrite, including cadmium and arsenic sulfides. These are very poisonous.
You are probably safe handling gemstones and semi-precious stones such as citrine, zircon, beryl, and amethyst – these are typically hard minerals that do not interact much with the environment nor degrade with time, which is why they are valued in the first place. 
I would encourage you to think more about a high-quality respirator when in a dusty, mineral-laden room. Inhalation is probably a more serious threat than getting the stuff on your hands… unless (like me) you always have an itchy nose and rub it frequently. Here is a website that will get you started on the various kinds of respirators out there (they run the gamut from the kind your dentist uses to serious industrial equipment): https://www.osha.gov/OshDoc/data_Hurricane_Facts/respirators.pdf 
Putting stones and gems in drinking water also boggles MY mind. A diamond will not react, and most semi-precious stones won’t either… but everything else WILL react with water to some degree, especially if the water’s slightly acidic (think Coke or Pepsi for acidic fluids). Putting crystals on your body is silly enough… now imagine bright yellow or red minerals in your drinking water!
I hope this helps. I personally love rock shops and as a geophysicist visit them whenever I can. I DO wash my hands after I leave one, however.