Thanks Werecow, I'll read through some of those blog posts. I was looking at a similar website with a contrarian flavour https://wattsupwiththat.com/ (which is not as well formatted as skepticalscience but has a variety of articles from the "other side").
Yeah, wattsupwiththat is one of the most well known climate science misinformation blogs out there (though there are a lot of others like climateaudit and junkscience), and Anthony Watts is notorious for cherry picking and other such shenanigans.
Unfortunately, during a particularly depressing episode in the climate change denial revival years during the Bush era the blog once got one of those "best science blogs" awards, for his cynical project of having non-experts go out to inspect temperature sensors and document anything that might be used to cast doubt on temperature records, and play up the urban heat island mythos (which is kind of like giving the discovery institute a "science institute of the year" award because it produced work that challenges evolution). This did not work out because climate scientists had of course long been aware of this issue and had already tested for this effect and found that their records looked nearly identical even if you didn't include any urban areas. This was mostly put to rest when then skeptical physicist Richard Muller did his own temperature reconstruction (with the arrogant acronym "BEST") and came to the exact same conclusions for the exact same reasons.This guy
(and skepticalscience) used to do frequent takedowns of Watts, e.g.:
My main point was that the distribution is unknown so talk about fat tails is unhelpful in describing the possibilities (of course we are much more captivated by extreme scenarios of by novel results);
There's a lot of unknowns here, but we're not entirely in the dark; we have palaeoclimate data that tells us that, for example, meltwater pulses and rapid temperature swings can occur. Ignore that data at your peril.
the current evidence does not point to any major catastrophe even events are often conflated with AGW (even Obama who mentioned his daugter's asthma as being somehow AGW related http://www.chicagotribune.com/news/nationworld/chi-obama-climate-change-20150407-story.html ) and the consequence for our Earth.
Well, I guess that depends on your definition of "catastrophe". Certainly the high end predictions sound pretty disastrous to me. But re: Obama, I feel the same way about him as I do about Al Gore (or anyone, really); I care about their opinion on climate change only to the extent that they can demonstrate their knowledge of the subject (I've actually managed to avoid watching An Inconvenient Truth to this day).
The sea levels have been rising by 3.5mm per year and models show increases of 20cm to 2.0m by the end of the 21st century and yet coastal real estate is increasing around the world so the investors must have a low sensitivity to climate change or feel that future adaptation and/or mitigation will be sufficient.
are certainly concerned (because of this
, for example). As is the U.S. military
There are certain advantages to living in a coastal area; there's a lot of opportunity for industry and trade, and the climate is generally milder because the ocean is a big heat store. In the U.S. "coastal and ocean activities, such as marine transportation of goods, offshore energy drilling, resource extraction, fish cultivation, recreation, and tourism are integral to the nation's economy, generating 58% of the national gross domestic product (GDP)"
. Population densities in coastal areas are about three times higher
than the global average. In the U.S., approximately 25 million people
live in an area vulnerable to coastal flooding. And of course there are more and more people, with more and more money to spend worldwide. So I am not surprised that there would be an increase in coastal development. And I doubt that most wealthy investors are young enough that they are highly concerned about events that will start becoming important decades from now.
In the short run, beach front property (for example) is probably not such a bad investment. People like the beach, and that's unlikely to change any time soon, especially as the climate is getting warmer. In the long run, you might end up with wet feet, but there's plenty of time to sell between now and then.
Such a slow change in sea levels could easily be adapted to - I fail to understand how such a slow increase in sea levels is such a pressing concern and, to my understanding, that is one of the most feared outcomes.
You may feel that way, but many experts disagree. I live in the Netherlands, where 2m of sea level rise is a really
big deal. We might
be able to adapt to one or two meters, because we are relatively rich, but probably not to the next 5 meters that will come from the likely melting of the Greenland ice sheet and parts of Antarctica over the subsequent centuries. The rise in sea level doesn't just stop after a hundred years. At some point, raising your dikes a bit more just doesn't do the trick anymore.
And what about the 200 million people who are predicted to be displaced in Bangladesh, a region of the world that is already overcrowded, with two nuclearized countries that have consistently been on the edge of war for years now? When I was last active in this debate, this was named by top U.S. military officials as one of the biggest threats to long term global stability.
And of course, we've all heard about the "sinking" island nations in the pacific that stand to lose their entire country. Also, keep in mind that the oceans are not flat, and as a result sea level rise can be more dramatic in one place than another.
And it's not just that the sea will encroach on our coasts; rising sea levels can seep into and contaminate freshwater aquifers that contain most of the worlds drinkable water, making them saltier. It'll change soil chemistry.
And sea level rise is not the only danger imposed by meltwater; the inpour of fresh water from the ice shelves (and smaller glaciers, and even the melting of sea ice) will make the Arctic surface water less saline, which will likely weaken the AMOC (which is driven in part by differences between deep ocean and surface salinity, and in part by temperature differences) and disrupt one of earth's major processes of heat redistribution (which is largely responsible for Europe's mild climate), which can have unpredictable effects (a similar disruption of the AMOC is implicated in Dansgaard-Oeschger events, rapid climate swings at the end of the last glacial period - though these are not thought to be likely to repeat themselves).
If the worst case scenario is significant ice loss and some increase in sea levels (with the IPCC scenarios, apart from RCP8.5 which from the assumptions appears to be extremely unlikely, having less than 2.5*C by 2100 and 3*C by 2300 - an absurdly long time scale to predict) what are the impacts on the Earth as a whole and humanity in particular?
First of all, bear in mind that the temperature change is not uniformly distributed across the earth's surface, so a 3o
C warming can mean 1o
C in one spot and 5o
C in another (or even 1o
C cooling in one place and 7o
C warming elsewhere). So the local impacts can be more severe than you'd expect from just the 3o
C number alone.
Second, the IPCC's WG2 report is dedicated to enumerating the impacts, and it is nearly 2000 pages long (it's even more huge than that WG1 report that cuts off my bloodflow), so any short summary will fail to do it justice, but the skepticalscience post on "it's not bad"
gives some highlights (though it's based on the AR4, so there have undoubtedly been some developments since then). If you want more detailed information, I recommend checking out the summary for policy makers
or even the technical summary
(which is more detailed).
The severity of the impacts depends on whether we make an effort to curtail the effects. The predictions for the higher end scenarios (which are not unrealistic under a business as usual scenario) paint a very unpleasant picture for the biosphere, of which we are a part, and many of these begin to play a role above 2o
C of warming, which is why that tends to be the target for many policy makers.
A big problem is that global warming puts various additional strains on ecosystems that are already under stress. For example, we know that our ocean ecosystems are in trouble, largely because of overfishing. CO2
comes along and causes coral bleaching through global warming, and ocean acidification. And there are reasons to believe that climate change will adversely affect the bottom of the ocean food chain
More erratic weather patterns will put stress on plants (including many food crops). Animals that have little room left for adaptation (like those living on mountains or in lakes that can't easily migrate) may go extinct. Many animal species are at risk of extinction. The IPCC AR4 notes that "There is medium confidence that ~20–30% of known plant and animal species are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5 °C to 2.5 °C over 1980–1999". Of course, ecological systems have similar chaotic aspects as the climate itself does, so who knows what the downstream effects of that could be.
Risks of extreme weather events, droughts, floods, and wildfires will increase, and with it the costs of the damage they cause (that's what worries re-insurers like Munich Re). Infectious disease territories may spread. Heat waves have in recent years been responsible for more deaths among the elderly. And so on. And it's worth pointing out that the people most at risk tend to be those who have benefited the least from the industrialization that has caused the problem (in large part because they don't have the means of adapting to climate change and because they already live in ecologically and economically stressed areas).
It's true that a lot of the impacts are highly uncertain, but the uncertainty goes both ways; that is, it could be much better, but it could also be much, much worse than we've anticipated. Unfortunately, the probability distribution for climate sensitivity is asymmetric, in such a way that there is a higher risk of it turning out higher than we think than there is of it turning out lower than we think (i.e., a fatter tail towards higher sensitivity than towards lower sensitivity).
In short, it's a huge
gamble to take, considering that the costs of mitigation are currently really not that draconian (yet).