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Extinctions Due to Global Warming Predicted
PizzaFace writes "A study being published today in Nature predicts that global warming will doom 15 to 37 percent of plants and animals to extinction by 2050, according to various news sources. The study looked at how predicted warming would affect the suitability of the areas that particular species inhabit, and whether displaced species would be able to migrate to suitable habitat. Many of the unlucky species are being caught between the hammer of global warming and the anvil of habitation destruction." The BBC has a story about climate engineering: long-range planning on making major changes in order to reduce the effects of global warming.
~50 years is a remarkably small time span to lose that many species, even in theory. It takes many, many generations for enough reproductive barriers to stabilize to make one recognizeable species... for this much genetic diversity to be lost would be a true catastrophe. If these theories are even remotely true, this is not something that should be brushed off with a "Life is just adjusting to new conditions"... this much "adjustment" to one life condition leaves what life that survives afterward vulnerable in their new monogenetic state.
It will be good for some species of reptiles and fish though. Though algea blooms might kill off even those fish that live, and a lack of prey may hurt the reptiles.
Ryan Fenton
About 100% of living organisms die off every few hundred years. From the Zoology course I just finished (I'm no expert), it takes a whole lot for a new species to develop. Just from your own experience - for wildly-reproducing fast-dying species, like say the common cold, you get one new noticeable strain every few years - and that's actually from a lot of sources, so the mutation rate there is actually much less often for a new true species to develop. A couple hundred years would not create 15-30% more species there.
For insects, the process would be slower - they only reproduce one to a few times a year, with an order of magnitude less reproduction, because they tend to live more successfully than bacteria. If you have ever studies fruit flies in a science class, it's not rare to see mutation - but to see a beneficial mutation is rare, and to have those build up to the point where groups grow so different they cannot reproduce together would take a long time. We don't tend to see completely new species of insects pop up in areas that have been observed... only shifts in populations. A couple hundred years does not create 15-30% more species there.
Mammals take MUCH longer to reproduce and live. In our own recorded history, we've never found groups of humans that could not inter-breed. In our history of dog breeding, it takes dozens of generations of carefully controlled breeding to even intelligently select one trait in one species of dog, often at cost. A couple hundred years would not even come close to 1% more species there.
I didn't study plants, but I don't believe they multiply or mutate at a higher rate than those animals.
Perhaps the study is wrong - but it's warnings ARE more dire than is gong to be fixed with natural diversification, from what little I know.
Ryan Fenton
BTW, my field is ichthyology, specificly the ichthyology of fluvial desert enviroments. The *main* limiting factor to a species distribution is not directly enviromental ( that is the organism can live in far greater range then it is found in), but competition from organisms more suited to the marginal enviroments. The study is flawed ( at least from cursory reading) because it does not take this into account. The other thing that the artical does not take into account is the introduction of organisms into new areas attributable to human activity. This is normaly concidered detrimental, but it can have positive aspects. An example is Ameca splendens, a fish well established in florida ( and the aquarium trade) but concidered extinct in its native waters.
The final problem is that the authors are relying on a meterological model that is not conciderd very likely by meterologists. In fact, most models show a wide variety of changes, most related to more dynamic weather. This makes sence as most of the extra energy will be goining into driving weather and not just increasing average global temerature. The earths climatic systems have a huge amount of negative feed back. I happen to be aware of this sort of thing becaus my last area of study was the effects of micro-weather on fish distributions.
I, for one, am much more concerned about the direct effects of human activity on animal populations. City heat island effect, ground water depleation, irrigation, river daming, deforestation, and deliberate non-native organisim introductions ( though the later is benificial to the introduced species, it can be hell on natives, especialy in areas severly modified by human activity) will do more damage in the next 50 years then incresed atmospheric CO2.
One more thing; Most of the models I have looked at indicate that the enviroment of the part of the world I am from, will actualy return to more historicaly normal conditions. This could include the expansion of a very special subtype of the sonoran that is rare in the US, though was not so 10K years ago. This would include the expansion of the range of some realy cool species.
This is not true. You can look at the atmospheric CO2 concentrations before and after any major eruption in the last 50 years (the time during which CO2 has been continually monitored around the world) and see that the amount of CO2 you are talking about was not released into the atmosphere.
Over the past 100 years, fossil fuel burning has released somewhere around 170 gigatons of carbon into the atmosphere. If a volcanic eruption released this much carbon, it would increase the CO2 concentration from 360 parts per million to 440 parts per million. That didn't happen.
You can also go back 500,000 years using glacial ice cores and see that the CO2 concentration never approached its current value during that time, even though there were many portions of that time span during which volcanic activity was much greater than it is today.
Also, water vapor is a more effective greenhouse substance than CO2
But the concentration of water vapor is limited by the saturation vapor pressure. If I dump a whole lot of water vapor into the atmosphere, the excess will precipitate out. The residence time of a water vapor molecule is quite short.
On the other hand, CO2 is not a vapor at room temperature, it's a gas. Its atmospheric residence time is much longer, so CO2 emitted today will be around for 50-100 years.
Finally, becauee small warming caused by increased CO2 causes the saturation vapor pressure of water vapor to rise, the water vapor effect amplifies the effect of CO2, causing approximately double the warming we would see with CO2 alone. This has been experimentally verified in studies of the troposphere following the Mt. Pinatubo eruption.
Finally, I would point out that chemical analysis of glacial ice cores demonstrates that over the past 500,000 years, whenever CO2 concentrations were high, temperatures were high. Whenever CO2 concentrations were low, temperatures were low. During ice ages, CO2 concentrations were exceptionally low. During interglacial periods, CO2 concentrations were high.
Today, CO2 concentrations are about 30% higher than they were during any time in that 500,000 year record. Because the oceans take a long time to heat up, we will not see the full warming due to the current CO2 concentration for many decades, but it is a great stretch to assume that the mechanisms that regulated the ice ages will suddenly stop working and fail to deliver substantial warming over the next century.
We don't know how much rain they'll be next Wednesday, but we can estimate the total rainfall for February very accurately.
Write out 100 times: Climate is not weather.
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