The seas are rising at a faster rate right now than at any point since at least the era of Julius Caesar, and there is a direct link between this increase and changes in global surface temperatures, according to a new study. Rising sea levels could have major impacts on not just marine ecosystems, but the entire planet, as coastal areas are swamped by encroaching waters.
The findings will help improve climate models and scientists' understanding of future sea level changes due to human-caused climate change. Until now, studies of sea level rise have been largely limited to satellite data, comprising a couple of decades, and tide-gauge records, comprising about 300 years.
Sea level increase is one of the most threatening aspects of climate change. Increases in global average temperatures will cause ice sheets to melt, gradually increasing the average height of the oceans and inundating coastal areas across the globe.
Sea levels were stable from at least 100 BC to 950 AD, according to Benjamin Horton, a professor of earth and environmental sciences at the University of Pennsylvania who co-authored the study, published in the Proceedings of the National Academy of Sciences. The levels rose a bit for the next 400 years, during a warm period known as the Medieval Climate Anomaly, and then they were stable again throughout the Little Ice Age, which lasted until the late 1800s. Since the onset of the industrial age, sea levels have risen by more than 2 millimeters per year — by far the steepest increase in the past 2,100 years.
"For the last 1,000 years, whenever temperature has changed, sea level has changed," Horton said in an interview. "It's a huge body of evidence to say that in the 21st century, with temperatures shown to be rising, that sea levels will rise. That's a great worry that comes out of this study."
To reach this conclusion, Horton and colleagues at the University of Pennsylvania, Penn State, Yale University and institutions in Germany and Finland studied core samples taken from the salt marshes of North Carolina's Outer Banks.
Salt marshes contain plants and bacteria that respond in measurable ways to changes in salinity, so their location at various sediment layers can provide clues about sea levels. Horton and colleagues studied microfossils called foraminifera that were preserved in the sediment cores. The sediment samples' ages were determined with radiocarbon dating, Horton said.
"As you go deeper and deeper, you go back through time," he said.
Although humans may not have disrupted the land, hurricanes have certainly taken their toll on the Carolinas several times in the past two millennia. Powerful winds and waves could have shifted the sediment layers, interfering with history. To account for this, the team drilled samples at sites that did not face the ocean, Horton said. He added that hurricanes would leave an obvious imprint in the core samples, with large grains of sand rudely embedded in the soft deposits.
The researchers drilled core samples several feet deep, and stopped at a depth equivalent to 2,000 years of sediment deposition. This is a much shorter time frame than the typical core samples taken from Arctic ice sheets, but it's easy to correlate to known historical temperatures, Horton said.
After accounting for naturally occurring subsidence, Horton et. al found that sea levels rose an average of 0.6 millimeters a year from about 800 AD-1080 AD, for the following 400 years.
"If you look at our sea level record, the first acceleration is around 1000 AD. What we would expect is that temperatures would be warming, and we know they are, during the medieval warm period. You can assume that the oceans expanded and the ice sheets melted. Then you have a period of stable sea level, which coincided with the Little Ice Age — the oceans may have slightly contracted, so the sea level corresponds to that," Horton said.
After 1850, temperatures began to rise, and so, too, did the seas, Horton said. Incidentally, Penn State climatologist Michael Mann, who helped create the famous "hockey stick" graph of temperature trends over the past 1,000 years, is a co-author on this study.
In some ways, the correlation should not be surprising, Horton said.
"It's evidence to support the obvious. The basic laws of physics say if you increase temperature, ice will melt," Horton said. "But what we show is how sensitive sea level is to changes in temperature. The medieval warm period was a very subtle change, but it results in a response in sea level. It indicates that they are intrinsically linked, and it's a very sensitive and instantaneous response."
Despite this strong correlation, the study is mum on future sea level projections. The data will serve to improve the models that will predict those increases, Horton said.
The research was funded by the National Science Foundation and published in this week's issue of PNAS.
I wonder how much of this is due to subsidence.
I dont care what you dummies say global warming (or at least somthing thats thinning the earths atmosphere causing tempetures to be in extremes depending on the season) IS hapening its not just because of cars its also because of killing marine life that produces oxygen, cutting down huge traks of land in the rainforsest(nicknamed the earth's LUNGS) witch kills all those oxygen producing trees and having way to many coal/oil factories spewing tons of carbon every second and if you totaly refuse to belive isn't it better to be safe than sorry because last summer we had record temptures in the high and last winter we had enough snow in most states that schools all over the country were closed these past years hurricanes,torados,earthquakes,and other natrual disaters have been incresing in occurnce AND strength don't you think SOMTHING is happening?
Global warming is a myth its not real tempeters have been rising scince before cars this past year was just a shit in tempeture change that is happening gradually for a long time people who belive global warming are no better than mindless sheeps
Please don't do that ^^^^^^^^ above me beacuse if you want to argue DON"T just keep your opinions to yourself
sorry if i seemed more biased towards the global warming is real side it's just that people who belive it let off alot of steam that i put here. and by the way when i sad shit in temputures i ment shift
Dont worry, this is happening.....
A new ice age? Man, its all speculation, and really not worth worrying about. I swear people just feed off "Doom and Gloom" scenarios....if that's the case just give us the Zombie apocalypse...lol
*sigh* Of course the Earth has gotten warmer over time - we're in a freaking interglacial. Any geologist will tell you that that's what happens when the planet is between ice ages. I learned that much in high school. Acting like "climate change" is a shock makes even less sense. The climate of the Earth has been continually changing ever since the Earth HAD a climate. In fact, I'd be much more concerned if the climate ceased to change over time. That'd be a first in the history of the planet.
No, the question here is not whether or not the Earth is gradually getting warmer, but rather how much of that is natural and how much is due to human influence. Until we have irrefutable data to prove that any given change in the global climate is primarily our fault, we have no reason to panic and do something drastic on a massive scale. That would only lead to equally massive unintended consequences, and the cure could very well end up killing us faster than the disease. As of yet, there is no such irrefutable data, therefore there is no cause for panic. The name-calling and demagoguing needs to stop, so we can investigate the matter in proper scientific fashion and take appropriate measures based upon the results. Anything else is a waste of time, money and brain cells.
have Republicans stopped debating about global warming yet...
i think its funny. just 2 years ago people were spending MILLIONS of dollars arguing that global warming was a myth. I bet they wish they had that money to pay for extra air conditioning.
then agian global warming might still be a myth. it could just be god snapping his fingers, you know like creationism and thats real isnt?
I don't care if it's human caused or natural. The truth is that the climate is changing faster now than at any other point in 'modern' human history. Our entire cilivilization of 7 billion people is based on a climate that is quickly changing and unless we can change our entire civilization (farming techniques, living on eroding coasts etc) we're going to continue to see massive disasters like Katrina or Japan.
The fact that the overall temperature of Earth is rising has been proven over and over et nauseum. If you look at historical records back hundreds of millions of years you can see that the only times that temperatures ever increased this quickly were natural disasters such as super volcanos and meteor strikes. So one could say that we as modern humans are just natural disasters.
Yeah we should really stop using fossil fuels and also stop building realstate on subsiding coastlines all the time... I guess eventually people will learn.... eventually, after much loss..
the only way we can reverse this is if we all stepped back and lived like tribesmen and women.
now who's with me?! *look left n right* thats right no one has the balls to do this, so this planet is pretty much scccrrrewed. our futures are sccccreeeewwwwwedddd.
and that weeks long tornado extravaganza in the US on May 21 onward was a magnificently scary preview of what the future brings.
Well 2 mm per year definitely indicates a warming tsunami is upon us and threatens to drown everyone. LOL.
Hey change happens it's the way of nature, the way of life, get used to it.
If we all take turns holding our breath (called skip-breathing in diving parlance), we can lower the CO2 released into the atmosphere and the world will get cooler.
I noticed some people believe the best was to fight global warming is to live as the caveman. This is not true, in fact that would make it much worse. The resources that are used by individual fires to cook and heat your cave would be astronomical in comparison to what we do today. Anyone in a large city of the 4th of July in the US could understand this, think of smoke twice as thick, day and night everywhere. Not to mention the amount of rain forest wood needed. Technology reduces our foot print, but it is a game, who grows faster, the population or our ability to reduce resource needs and carbon foot print.
If we'd entirely bomb developing countries, there'd be a couple billion people less producing CO2 and stuff. That should buy us some time to think!
"historical records back hundreds of millions of years"?
You'll won't find much historical records of that era... (Hint: There was no humans that long ago!)
We'd still need to wipe our ar*es with somthing! Leaves would be a good idea but we'd still be hurting those poor trees!
Paging Mr. Camping... I wonder how much money Al Gore has made off of "Global Warming" and "Greenhouse Effect"? Or, how much fossil fuel he has used flying all over the world to warn us that driving SUVs is bad for the environment? Hey buy my product its made from recycled materials so its better for the environment, only 39 cents more. Why don't we have chain gangs picking up trash on every major coastline? Why did we ban drilling in the Gulf after the BP oil spill but there is still a not so small island of TRASH in the middle of the Atlantic? This is a marketing ploy and nothing more. We are very much responsible for reaping the natural resources of our world but short of global nuclear war, I do not think we have essentially shot ourselves in the foot.... yet. Besides, if there is real physical evidence that we have caused these sudden natural disasters, its already too late. The world is full of stupid people, and relative to this article, I hope they live on the coast.
Nothing mankind does (other than nuclear holocaust) matters AT ALL in a geologic time-frame... all this hand-wringing and lamenting over man-made 'disasters' helps not even the tiniest bit towards making life better for us while we're here.
But it sure is fun, especially the infantile name-calling.... bunch of stupid rejects lol
The world is heating up because the sun is heating up. The global warming scenario has a few agendas. To control population. To control the progress of developing worlds. To raise funds (via carbon tax) for government programs.
The government knows that the sun is heating the earth up. That's why there is an extensive chemtrailing program going on in developed nations.
yes the sun is whats causing most if not all of the earth warming. its basically the lifeline of earth. the heart.
Guys, listen up, because here is MY argument: Would you hang out in your garage with all doors/windows shut and your car running? How about an enclosed stadium? Why should this fishbowl of a planet be any different? I mean simply, if I pee in the ocean, I'm peeing in your water. If I throw litter on the ground, I'm littering and making dirty and ugly your planet. What is really the issue is getting around capitalism, because at its worst, capatilism causes reckless methods of obtaining wealth, from strip mining, to hydro mining, to deforestation, etc. I live in CA, and every time of year, about now, the butterflies used to migrate in the millions. I've seen a couple this year... but not enough to darken the sun like in times of old.
We have helped more species join the endangered species list, and have caused even more to become extinct. The problem is that we will all have to sacrifice a little to make this happen, but if we don't do it, well, nature will restore balance, whether thru boiling off that atmosphere, or plunging us into another ice age, it will happen.
Consider instead, trying to live with our environment, instead of changing it to meet our desires. Shoot, in the hot places where we run A/C a lot, how about enough solar panels to run just the compressor for the A/C, so that HUGE load can be taken off the grids?
We as people get so caught up in fighting over who to blame, that we don't bother to come up with a solution, or sadly, we can't agree on a solution. Anyway, I'll step off my soap box, but this isn't one to be taken lightly,
and @shutterpod -> I wish we knew which niche of life you survived in, because I'd kill off your dependencies! Wow, you were right! Name calling can be fun! :P
OK, this is good. We now have reasonable information confirming what we already suspected; The oceans have risen about 8 inches over the last 100 years; higher temperatures melt more ice. Most of us can agree with this. Now, as to the hyperbole, such as .. sweeping damage this sudden influx of water will have to our coastal regions and "Most threatening aspect of climate change". Also, why do we only care about human caused sea level change as noted in the article?
Another thing that gets me to giggle is the 2100 years. I would have rounded it to 2000 years out of humility (and it would also match the picture's subtitle). I could easily say that this is not the fastest rate of sea rise in the past 2200 years based on the article. Glad we survived those years! For those interested, have a look at the sea rise chart over the past 10,000 years - we've made it through some tough times!
Cold fusion featured in the LA Times in '89 before it was debunked. Environmentalists were aghast at the possibility of cheap clean energy:
“It’s like giving a machine gun to an idiot child.” – Paul Ehrlich (mentor of John Cook of the SkepticalScience blog, author of "Climate Change Denial")
“Clean-burning, non-polluting, hydrogen-using bulldozers still could knock down trees or build housing developments on farmland.” – Paul Ciotti (LA Times)
“It gives some people the false hope that there are no limits to growth and no environmental price to be paid by having unlimited sources of energy.” – Jeremy Rifkin (NY Times)
“Many people assume that cheaper, more abundant energy will mean that mankind is better off, but there is no evidence for that.” – Laura Nader (sister of Ralph)
CLIMATEGATE 101: "For your eyes only: Don't leave stuff lying around on ftp sites - you never know who is trawling them. The two MMs have been after the CRU station data for years. If they ever hear there is a Freedom of Information Act now in the UK, I think I'll delete the file rather than send to anyone....Tom Wigley has sent me a worried email when he heard about it - thought people could ask him for his model code. He has retired officially from UEA so he can hide behind that." - Phil "Hide The Decline" Jones to Michael "Hockey Stick" Mann
Here I present The Quick Glance Guide to Global Warming:
-=NikFromNYC=- Ph.D. in Carbon Chemistry (Columbia/Harvard)
A good sea level debunking blog is at: http://climatesanity.wordpress.com
I got screamed at on an AGW enthusiast site, told I should be ashamed of myself, that I was stupid, that I didn’t really have a Ph.D., that blah blah blah…for posting a chart of representative tide gauge records (http://oi53.tinypic.com/2i6os4y.jpg). However, the one valid point was a lack of publishing my collection in the literature. Well, I thought, let’s dig a few sea level studies up then. Imagine my surprise to not find just linear trends but universal signs of recent deceleration!
(1) Church and White, the classic purveyors of an exponentially shaped sea level curve, in their latest article update of 2011 (which eliminated the word “accelerating” from the title) plots, in hard-to-see yellow, a simple average of tide gauges, which, once I clean all the dark plots behind it away, shows stark linearity.
(2) Sea levels show deceleration since 1930:
That’s the USA and Pacific Ocean, and says: "Least-squares quadratic analysis of each of the 57 records are performed to quantify accelerations, and 25 gauge records having data spanning from 1930 to 2010 are analyzed. In both cases we obtain small average sea-level decelerations."
That’s Australia (deceleration since 1940) that says: "The analysis reveals a consistent trend of weak deceleration at each of these gauge sites throughout Australasia over the period from 1940 to 2000. Short period trends of acceleration in mean sea level after 1990 are evident at each site, although these are not abnormal or higher than other short-term rates measured throughout the historical record."
That one says: “Unambiguous evidence for fingerprints of glacial melting was not found, most likely due to the presence of other signals present in sea-level records that cannot easily be distinguished.”
That one is Europe and says: “no evidence was found for MSL accelerations significantly different from zero over the period 1870 to the present.”
That one is a world wide sampling that says: “The rate of sea level change was found to be larger in the early part of last century.”
That one was the Pacific based on the longest records available which says: “The estimated average rate of sea level rise from the longest records is computed to be +0.3 mm/yr, almost an order of magnitude less than the IPCC estimates.”
That one was Europe and N. America which says: “Most sea-level data originate from Europe and North America, and both the sets display evidence for a positive acceleration, or ‘inflexion’, around 1920–1930 and a negative one around 1960. These inflexions are the main contributors to reported accelerations since the late 19th century, and to decelerations during the mid- to late 20th century.”
(8) A study by one of the RealClimate team (Rahmstorf 2007 as discussed on http://climatesanity.wordpress.com/). He got his acceleration via adjustment to *actual* sea levels to account for land based water reservoirs while ignoring ground water pumping to the surface. This swam right through peer review. Such adjustments are highly speculative at best and simply fantasy at worst for they do not reflect *actual* sea level changes!
Thanks for the information site references. I always like to read both pro and con.
It'll be interesting to see how many trillions of dollars will be needed to pay out insurance, because of flooding, and keeping the water out. Well, apparently there are people who prefer not to spend those trillions now on possible remedies but just sit on the tracks and wait for the train to arrive. I, for one, can't wait to visit Times Square in a gondola.