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Discussion in 'Weather and Surf Forecasting' started by Swellinfo, Oct 31, 2011.
anybody seen "collapse" on netflix? The interveiw with Micheal Rupert?
If you like that documentary check out his books. I had the opportunity to meet him last spring when he gave a lecture at the University of Delaware.
it gets cold in the winter and hot in the summer. i agree that our pollution has effects but it seems a little arrogant to think that we humans can have such a profound effect,positive or negative,on something as huge as our atmosphere.i also doubt cow farts are that gnarly
Just take the assumption that climate change is a bad thing. Then the opposite (or good thing if you will) would be a static climate, but a static climate is an impossibility (evidenced by changes in seasons). So the idea that climate change is unprecedented and new, and something to get worked up over seems silly to me. Does one just assume that climate was static prior to rises in anthropogenic pollution sources? Doubtful. I think the fact that climate was changing long before we were contributing anthropogenic sources is ignored. Do I believe that humans have contributed to the rise in CO2 levels? Sure, the data doesn't lie (although it can be manipulated to serve different purposes, as every good modeler/statistician knows). It has been proven that anthropogenic sources have elevated carbon levels in the atmosphere and can contribute to radiative forcing (i.e. warming). That said, I do not believe that anthropogenic sources are the primary driver of climate change. And I don't think the meteorological climate record goes back far enough to say otherwise. 150 years is a drop in the bucket when considering the age of the Earth. I think Milankovitch cycles can account for the periods of glaciation and hot-house climates that are evidenced in ice-core and deep-ocean core records. Milankovitch cycles can explain climate changes in Earth's history (primary driver being changes in the Earth's orbit) and there are core records to back it up. Is it a perfect fit, no? But it makes a lot of sense when considering changes in Earth's climate throughout Earth's history versus the last 50-75 years.
"A common skeptic argument is that climate has changed naturally in the past, long before SUVs and coal-fired power plants, so therefore humans cannot be causing global warming now. Interestingly, the peer-reviewed research into past climate change comes to the opposite conclusion. To understand this, first you have to ask why climate has changed in the past. It doesn't happen by magic. Climate changes when it’s forced to change. When our planet suffers an energy imbalance and gains or loses heat, global temperature changes.
There are a number of different forces which can influence the Earth’s climate. When the sun gets brighter, the planet receives more energy and warms. When volcanoes erupt, they emit particles into the atmosphere which reflect sunlight, and the planet cools. When there are more greenhouse gases in the atmosphere, the planet warms. These effects are referred to as external forcings because by changing the planet's energy balance, they force climate to change.
It is obviously true that past climate change was caused by natural forcings. However, to argue that this means we can’t cause climate change is like arguing that humans can’t start bushfires because in the past they’ve happened naturally. Greenhouse gas increases have caused climate change many times in Earth’s history, and we are now adding greenhouse gases to the atmosphere at a increasingly rapid rate.
Looking at the past gives us insight into how our climate responds to external forcings. Using ice cores, for instance, we can work out the degree of past temperature change, the level of solar activity, and the amount of greenhouse gases and volcanic dust in the atmosphere. From this, we can determine how temperature has changed due to past energy imbalances. What we have found, looking at many different periods and timescales in Earth's history, is that when the Earth gains heat, positive feedbacks amplify the warming. This is why we've experienced such dramatic changes in temperature in the past. Our climate is highly sensitive to changes in heat. We can even quantify this: when you include positive feedbacks, a doubling of CO2 causes a warming of around 3°C.
What does that mean for today? Rising greenhouse gas levels are an external forcing, which has caused climate changes many times in Earth's history. They're causing an energy imbalance and the planet is building up heat. From Earth's history, we know that positive feedbacks will amplify the greenhouse warming. So past climate change doesn't tell us that humans can't influence climate; on the contrary, it tells us that climate is highly sensitive to the greenhouse warming we're now causing."
I agree ^
Equilibrium seems to be natures goal.
If you take any fluid medium, and create imbalance by heating or cooling part of the fluid medium, the medium will change in order to return to an equilibrium state. Meaning if you heat part of the fluid, it will eventually disperse throughout the entire fluid medium.
Our atmosphere and oceans are no different. Our dynamic weather here on earth, is driven by the differential heating from the sun on the planet. Since the earth rotates around its titled axis every day, and rotates around the sun every year, different parts of the planet are warmed and cooled both diurnally and seasonally. Warm air rises, cool air sinks, and high and low pressure systems are created because of this to disperse the solar energy around the globe.
Clearly you both have good climate knowledge, so I can respect where you're both coming from. But I think my point has been misinterpreted. Since you have climate knowledge you know that past climate changes have occurred due to natural forcings. However, I think a lot of people are uninformed when it comes to the issue and they just presume that the climate change observed in recent times is something that has never occurred before and climate change can only occur because of anthropogenic sources. I think this is played upon in the politicization of the issue where the narrative becomes skewed and the science is ignored. And I don't disagree that anthropogenic sources have contributed to the rise atmospheric of CO2 concentrations, which I stated previously. Greenhouse gases are obviously a driver of radiative forcing, a positive feedback loop as you said. Can we influence climate, sure. But are we gonna send the earth into uncontrollable positive feedback loop where Earth is a permanent hot-house, ala Venus? Possibly, but the Earth is very dynamic. My main point was that climate is driven by many factors and even if anthropogenic sources are currently influencing the positive feedback loop, they are human-induced and they can be quickly trumped by mother nature. Just as the current rise in anthropogenic sources influence the positive feedback loop, a large-scale volcanic eruption could influence a negative feedback loop (think Little Ice Age from 1600s). Changes in the obliquity, eccentricity, and axial tilt of the Earth's orbit could influence a negative feedback loop. The growth of ice at one of the poles could enhance ablation and influence a negative feedback loop. The ice core records have shown many major shifts in climate over the last 500,000 years, which are shifts on a much grander scale than what we are currently observing.
Again, I'm not saying we should be naive and hope for a negative feedback to just magically kick in one day, nor am I saying we should disregard our anthropogenic sources. I just disagree with the drive to paint the current situation as a doomsday scenario that plays on people's emotion. I'm saying that climate is driven by a lot of things beyond our control, irregardless of how anthropogenic sources are handled in the future. But that said, I'm sure having our own emissions "house" in order wouldn't hurt either
The skeptics often point to the "oh, this has happened before argument". In terms of the quantity of heating, they are correct. Obviously the pre- and post- ice age periods saw profound mean temperature changes. The important difference between those events and our current situation is RATE. Anyone who studies science, from ocean currents to geophysics, knows that the earth normally changes slowly. In the case of the ice ages, we look at glacial advance and retreat occurring over periods between 40,000-100,000 years. Compare that to more recent warming trends, and we see it's a lot different. Also, people hear about a 1 degree mean temperature rise in the ocean and shake their head. Anyone who took chemistry in high school would have learned the simple yet telling specific heat equation: Q=mc(delta T). That is, to raise the temperature of a given mass of some material requires a certain amount of energy. For water, this energy is pretty friggen huge. To raise the mean ocean temperature by one degree is a big deal.
The reason we switched the terminology from "global warming" to "climate change" is not a retreat at all. It's a more practical term to describe the SYMPTOMS of global warming. When it snows, the pseudo-science GOP likes to go on Fox News and joke about "hahaha global warming, what a joke". The truth is, they hold a large stake in coal and petrol and will do anything, no matter how unethical, to keep burning the dinosaur guts. The term "climate change" is meant to more accurately portray our problems to the short attention span of most folks. I do not mean to say that people are stupid, but that they are easily manipulated. Why else would anyone vote for Rick Perry? If the scientific community leaves any room for biased parties to skew the results in a dishonest manner, the interested parties will seize the carpe and deceive the electorate. Hence, "climate change".
Another note: it goes way beyond climate change. Things like 'fracking' (for natural gas) destroy the water supplies of nearby communities. Gas station spills do the same. Did you know that hundreds of gas station spills occur every year? Did you know that just a few years back this happened to communities north of Baltimore City that rely on well water for their homes? Hundreds of these people now need to purchase bottled water to drink because even a proper filter cannot remove the additive chemicals used in petrol. They can't even shower in their homes because the chemicals are most potent when inhaled as part of the hot water shower steam. This stuff has already destroyed dozens of communities in our country, and there is no reason to believe that will change. Green energy is needed not only to limit greenhouse gas emissions, but because the extraction and distribution of fossil fuels create their own set of problems. If we continue to swim against the current instead of going "all in" to find a better way, than we doom ourselves. Just look at the people on both sides of the debate: one on side, you have scientists whose motive is to look at the world around them and objectively describe what's occurring and why, and on the other side you have people funded by the fossil fuel industries. It's not THAT difficult to see why the latter just might have a motive to 'make their own science'.
I'm not going to post anymore about this, but I will say thank you to Andrew for injecting some actual real research into the discussion. Please forgive me if I come off as harsh and/or dismissive. It just bugs me to hear people so fatalistic. There are MANY ways we can reduce our dependence on fossil fuels, and our long-term success as an economy and a community depends heavily on our ability to implement a more sustainable approach.
R.I.P. Andy Irons
The ocean levels have been all over the place for millions of years. California was once under water, along with the rest of the SW. Due to earthquakes, techtonic shifting and a million other factors, crevices in the ocean floor and other things have shifted the amount of water and levels around the world. Think of the impact of the giant tsunami triggering earthquakes etc....
Long, long before man burned fuel, the climate has change. The ice-caps were once all water... They froze over, now they melt slowly... seems pretty darn natural in the grand scheme of things...
The earth has been scorched. Life has been destroyed on land, all due to natural causes.... The earth was also a giant block of ice... then it warmed back up.... There are internal issues within the earth that we have no clue about.... When things go from one extreme to the other, nature takes its course and reactions happen... slowly.... very slowly.....
Sh**, didnt they just show a study that we havent even discovered like 750,000 ocean animal species....
We think we know everything... we do not... I try not to be a skeptic, but the climate has changed back and forth long before we populated it... There was no "man or animal" related influence... it was the earth and the atmosphere doing its thing... It will always do its thing.... we cant slow it, stop it or anything....
Sure, our pollution and discharge of fossil fuels is TERRIBLE.... but blaming climate change on a whole just require more proof and more science than people have been able to provide.... Its just peoples ideas... NO PROOF....
Yea... Earth's climate has cycled through warming and cooling for eons... Yes, the proof is in the rock record, ice cores, etc. and it's undeniable. Yes, Earth's climate is changing today, as we speak - again, undeniable proof (for anyone with an unbiased agenda). These are the facts, and "global warming" and "global cooling" are nothing new to Earth.
The difference is that WE are here now, and we weren't before. Seven billion of us! We've established ourselves on the face of the Earth because of where it rains, where it doesn't, where, when and how rivers flood and meander, where arable is, etc. Certain places on Earth are not hospitable. Others are. Combine that with the fact that we have an exponentially growing human population, and an exponentially shrinking resource base to support them. If climate change continues at it's current rate, it means BIG changes in both where and how humans live. This is also undeniable. It's certainly not the end of the world, but it's impact will be far greater and effect us much more quickly than we would like to think.
im not surprised no one responded to this. yes, the "evidence" shows a recent warming trend at an alarming rate, but this evidence comes from a decline of weather recording stations in artic areas and an increase of weather recording stations in warm tropical areas near large cities. no **** the average is going to be warmer than it was when there were more weather recording stations in artic areas and colder places
This reply is just to bring a little science to potential causes of climate shifts.
The movie, "The Day After Tomorrow", is a super dramatization that the climate is all of a sudden going to shift, because the Thermohaline circulation in the North Atlantic Ocean all of a sudden breaks down and essentially brings a major shift to the world wide weather patterns...
That was Hollywood of course, and nothing is going to happen overnight. But, it was based on the idea that the oceans play a huge role in our weather and regional climates. Unlike the atmosphere, water stores energy for a much longer time, as we surfers can see in the fall when it takes water temps off the East Coast longer much longer to cool. And, this is the just the surface temperatures... As a whole the ocean, which makes up some 70+% of the earth's surface is a huge storage of energy.
Water temps have large impacts on the regional climate of areas (west coasts see this more easily since weather moves from west to east). Take a look at Europe - England is further north in latitude then Newfoundland, but has a much more moderate climate. This is because the warm gulf stream provides relatively warm water off the west coast of Europe.
The gulf stream is more of a surface current, but the thermohaline is driven by ocean density differences by changes in thermo-temperature and haline-salt the create a huge conveyor belt of ocean circulation from the ocean surface to the ocean floors that are interconnected throughout all of our oceans.
Changes in the thermohaline circulation in the North Atlantic has been claimed as reasons for previous past climate shifts. In the present day "climate change", in the North Atlantic we look at ice melting (less saline = less density) and water temps rising (less density), which can change the sinking motion of the all important North Atlantic Thermohaline circulation.
So, I'm not replying to anyone in particular, I just wanted to offer a science example to how and why climate shifts can occur.
I wish global warming were legit. I mean real numbers, not inaccurate readings that have only risen 1 degree in how ever many years. As a scientist in the field (not in a lecture hall), the margin of error in these temperature readings from around the globe using various instruments are astronomical. So anyway, this sucks. I'm sick of the cold. I vote for a 30 degree above avg winter!!! And a bunch of Nor'Easters.
Yesterday was fun as hell, some serious bombs coming through. The water is getting cold from climate change (summer to winter). Wish I didn't have to work right now!! I should just go occupy wall street!!!
This is my favorite thing written on this damn website in a while.
Maybe i'll see you at OWS! ah wait, never mind, I'm going to go focus on improving my life for myself.
Unfortunately, that's what most people think could happen. However, a few degrees change in the climate of a large geographic region is all that's required to start seeing dramatic changes in short term weather patterns. As stated earlier, weather is the short term, localized manifestation of climate. Change climate, and you necessarily change weather patterns. So when I say, "more quickly... than we'd like to think," I'm saying in terms of generations, not thousands of years... too quickly to pick up a major metropolitan area and move it inland.
In our lifetime, we've already seen sea level rise. It's being measured by satellite as we speak... about 2 or 3mm/year, on average. That translates into the landward migration of the shoreline over time. I've seen the effects of it myself... in Cape May County, wooded areas adjacent to salt marsh that were once high and dry are now swamps where trees are rotting and falling into the back bays. That in itself is not such a tragedy, but you can assume that this is happening in many coastal plains around the world, where salt water is intruding into fresh water wells... where habitats are changing and endangering species... where agricultural land used to raise food or feed for animals is becoming less productive... where people are being forced to move from their dwellings...
And my guess is... to bring it all back into focus... shoreline ocean currents are changing, and changing the way sand moves and how the waves break. That's not such a big stretch of logic...
Respek da scientists!
Aloha everyone, 1st post.
If I may add my 2 cents to this discussion I'll just suggest this: Someone who's spent years studying for their PhD and then publishing peer-reviewed research is a bit like someone who's put in the time at a competitive break to get it dialed and earn their spot in the lineup. They're not gods, and some may be douchey, but still...
NADW and the conveyor belt
You hit the nail on the head, its all about the thermohaline circulation which at the surface is largesly a response to the overlying atmospheric circulation. However, the circulation of deeper waters is a conseqence of density variations which result from differences in temperature and salinty. In areas where surface waters become denser due to cooling/evaporation (increasing salinity) waters will sink to a level where they equilibriate with surrounding water masses. Additionally areas of sea ice formation produce brine which increase water density casuing water to sink and form dense cold water masses. These dense water masses flow away from their source areas. Much of the world's oceans are filled with Antarctic Bottom Water. In the Atlantic, the deepest waters are characterized by North Atlantic Deep Water (NADW) that form primarliy in the Norweigan and Greenland Seas.
The NADW forms north of 60N and the NADW water mass moves south at depth bringing cooler, saline water to the South Atlantic and other basins (at depth). This "loss" of cooler water in the northern lats is compensated by the poleward movement of warm saline surface waters to the North Atlantic (via Gulf Stream and/or North Atlantic Drift). These waters are responsible for the mild temperatures Western Europe experiences even in winter. The combination of NADW formation in the north and the movement of warm salty water to higher latitudes is considered a linked system, sometimes referred to as the NADW conveyor belt. Disturbances to this system can cause a change in its speed or even shut it down. In particular, the system can be quite sensitive to distrubances from freshwater inflows. Currently the North Atlantic Basin loses slightly more freshwater via evaporation than it gains frome either precipitation or river runoff. This combined with the flux of saline Gulf Stream water and strong cooling (as in winter) leads to NADW formation. However, were the freshwater flux to increase (as it has in the past when ice sheets melted), an upper, lower salinity layer would be created where this NADW formation would be altered, or shut-down. This would in a sense turn the conveyor belt "off" and a reduction in the flux of Gulf Stream water to the northern latitudes. This in turn means less heat transported to the North Atlantic and generally colder climates. Cold climates would continue until eventually salinity would gradually increase to some critical density whereby the conveyor would switch back on.
It has been postulated that this is what brought the last interglacial to a close (Cortijo et al., 1994; Shaffer and Bendstren, 1994). In addition to orbital forcing (reduction in summer insolation and and increase in winter insolation), a higher interglacial sea level would have led to an increased flux of water through the Arctic from the North Pacific bringing more low salinity water to the North Atlantic. Higher temperatures may have increased in evaporation and precipitation rates adding additional freshwater to the North Atlantic. It is thought that these factors would have been enough to lower surface water density and reduce or even eliminate deepwater production, setting the stage for renewed continental glaciation. Once temperatures fall, the evaporation rates would also have decreased allowing salinity levels to remain low. The only caveat to the above scenario is that all these factors are related in a positive feedback loop which makes distinguishing causes and effects, difficult.
So the take home reader's digest version is that the thermohaline circulation is a critical driver of climate but is also very susceptible to changes in freshwater/salinity fluxes. Were the climate to increase in temperatures to unprecedented levels, there would be an increase in freshwater influx to the system (due to higher temps). Over time were the flux of freshwater to become large enough it would trigger the slowdown or cessation of NADW production. The effects of this would reduce ocean circulation of warmer waters to higher latitudes. And turning off the conveyor belt could trigger a return to cooler climates (in the North Atlantic anyway). So in a way mother nature has a solution to changes in climate whether temperatures increase or decrease.