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Forums - General - Do you think humans are helping cause Climate change?

 

Are humans the leading factor in our changing climate?

Of course we are. 73 55.30%
 
Probably. 17 12.88%
 
Probably not. 12 9.09%
 
Absolutely not. 23 17.42%
 
I have no idea. 6 4.55%
 
I wanna change apms climate ;) 1 0.76%
 
Total:132
UltimateUnknown on 26 April 2012

Wow I just got done doing an entire module on environmental physics half of which was pretty much studying this topic. I would like to point out that although the main aspect in which humans do contribute to the environment is through CO2 emissions, it is rather a chain of feedback mechanisms that tends to harm the environment in the long run (CO2 itself is a very weak greenhouse gas). Examples such as:

-Warming due to CO2 leads to more evaporation of water and more water vapor in general in the atmosphere, Water is a much stronger greenhouse gas than CO2 and can cause even more warming.
-Warming leads to less ice cover. Ice cover normally reflects sunlight (by increasing earth's albedo) but without ice cover more radiation will be absorbed leading to more heating of the earth.
-The oceans themselves can absorb some of the CO2 but warming of the oceans means less CO2 can be absorbed my chemical reactions.

There are many more mechanisms but these are just a few. That said people often have the misconception that greenhouse gases are a bad thing, they are not. Without any CO2 (and other greenhouse gases), the earth's temperature would be approximately -10 degrees C making it uninhabitable, but the warming from these gases has made the temperature much more suitable for life to exist. But too much heating on the other hand would again make it uninhabitable (look at Mars and Venus, too much CO2 in their atmospheres). This is much more complicated of course affecting biodiversity, weather, etc. So we better not mess with the balance too much which the earth has kept for so long now.



 

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fordy on 26 April 2012
silicon said:
fordy said:
HappySqurriel said:
fordy said:
HappySqurriel said:

We can power the world on 5,000 tons of thorium per year and there are 34 million tons of thorium in the world which means we will run out of thorium in about 6,000 years ... I believe it is kind of foolish to worry too much about a problem that might occur thousands of years from now; we (realistically) have no idea what kind of technology people that far in the future will have to produce energy from alternative sources.

With where research was at in the 1970s before funding was pulled from thorium research (probably) because it could not be weaponized, we could have (probably) had viable large scale thorium reactors in the early 1990s. If we're lucky we will be in a similar position with solar and wind power in 2050, and (realistically) I can't see us getting there in our lifetime.


So if we're going with a new technology, why stick with just the one that would NOT require the changeover in a few thousand years? It woud, after all, stop yet another disruption of the energy market should such technology not be as ahead as you think (see "stagnation of technology" explanation in one of my earlier posts).

Renewable is getting closer to grid parity as we speak, and has the potential to get even cheaper. It's "exhaustion" time is when the sun consumes the earth in a few billion years (and that's providing we haven't found a new star to harness from). 

Heck, even the use of just photovoltaics needs a miniscule area of the earth to match out current energy output (in black):

I would rather use well understood, cost effective technology that can be produced today than waste money pushing energy technologies that are decades or centuries away from being cost effective. Eventually these alternative energy sources may be viable, but pushing them when they're not ready will only push energy costs on average consumers up and make them substantially poorer; after all, how "wealthy" would you feel if your total energy expenditure a month increased form $200 per month to $1,000 to $2,000 per month.

 


You just contradicted yourself there, since, as you said, Thorium breeder reactors would take more research, whereas photovoltaic is reaching grid parity within a matter of years for many major cities, not decades.

The map that I showed you is the surface area of photovoltaics needed that would produce the same amount of energy that humans consume through other means, if photovoltaics have an 8% efficiency. In the lab, photovoltaics are in the 40% efficiency range.

It's not "decades or centuries away from being cost effective", it's reaching that point quicker than you can tell.

Photovoltaics won't reach grid parity for a while, unless you look at countries with high electricity costs like Germany. Also, photovoltaics have 40% in practice too but they're expensive. It's a prive vs. efficiency. Anything higher then 8% costs too much to manufacteur or uses rare elements. 

Wind is already below grid partiy, the problem is that it only provide inttermittent power, or no efficient way of storing that energy.

Perhaps that's saying something, hm? That countries with cheaper electricity costs have not been absorbing the true costs of fossil fuel based energy generation? That those costs have been subsidised to buggery?

You're expecting me to have sympathy for those paying well below the global average, complaining that they no longer can? I mean, we only have to look at how many Americans kick up a stink when gas prices go up, yet it's still significantly cheaper than other places.

As for energy storage, there are two major technologies that I've seen that are being investigated:

- Ultracapacitors 

- Molten salt batteries



UltimateUnknown on 26 April 2012
Rath said:
Don't forget hydro power guys! Here in NZ the majority of our power comes from hydro. We only get about a third from non-renewable (mostly nat gas).

Although hydro electric is a very good source of power due to the high density of water and doesn't have some of the theoretical limitations wind power has, it is very very obstrusive to actually extract power from it. The dams that need to be built pretty much change the entire ecology of plant/animallife in regions where they are built. Not to mention these are massive projects. Also many areas just don't have access to actually extract power from water from what I can see. Its not as simple as sticking a photovoltaic on your rooftop (which in itself is unreliable in many ways).

The only form of power that I can personally see replacing fossil fuels on lare scale in the future is nuclear fusion but that always seems to be 20 years away no matter what era you live in.



 

Alby_da_Wolf on 26 April 2012

Thorium could be anyway a better choice than other non renewable sources, as backup in a system using mainly renewable but not constant sources. Obviously hydro, where viable, is better, but its viability as main source or main backup one depends on having a good amount of mountain waters and power needs not too high, it's perfect in countries with many mountains and not overpopulated.
And maybe the most important thing: whatever energy sources we choose, energy efficiency is of the essence.
High efficiency, for example, can make 2nd generation biofuels a viable solution for private transport, without high efficiency it cannot be. High efficiency doesn't just consist in the vehicle efficiency, but using the right vehicle for the purpose, that is, using a citycar, not a SUV, to carry few people and things for short distances and in urban areas.



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Rath on 26 April 2012
Kynes said:
Rath said:
Kynes said:

What people doesn't seem to consider is negative feedback. Higher sea temperatures increase the evaporation in the tropical areas, increasing the number of clouds and reducing the sun rays that reach the ground, cooling it. Higher levels of CO2 make forests and crop fields have higher yield, and this way the CO2 level reduces it's growth. We've had geologic eras with tens of times more CO2 in the atmosphere, with rain forests in the Sahara, with a much more green earth:

Is there a direct correlation of CO2 level and temperature? There doesn't seem to have a lineal correlation, at all. I think people are barking at the wrong tree, and lots of people believe we're much more important than we really are.


Clearly five hundred million years ago the system was very different - there was more methane in the atmosphere, there was less in the way of carbon dioxide absorbing life, the sun was at a very different point in its life cycle etc. Carbon dioxide would still have had an important part in the climate but the level cannot be directly compared to current conditions. If you want a real comparison look at more recent data such as that from the Holocene period.

Why we don't have this correlation today? In that graph we see differences of 20C related to differences of 100 ppm of CO2. If this were the truth, nowadays the Antarctica would be at -40C, as we have now ~400 ppm, and that's not what we see. May it be that the CO2 proportion in the atmosphere was related to the temperature, and not the temperature related to the CO2 proportion? There is a theory that implies that the oceans capture more or less CO2 in relation to the temperature, and it has approximately one thousand years of lag. If you take a look at the graph, it seems that the blue line follows the red line, and not the inverse.

That is because historically CO2 does lag temperature. Historically the initial temperature rise (due to a natural orbital cycle) has caused a release of CO2 which has formed a greenhouse effect causing more warming, releasing more CO2 - it forms a self reinforcing cycle. Humans are the anamoly in that we're releasing large amounts of CO2 without a preceding temperature rise, we're basically kick starting warming.



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Mummelmann on 27 April 2012
Rath said:
Don't forget hydro power guys! Here in NZ the majority of our power comes from hydro. We only get about a third from non-renewable (mostly nat gas).


Same here, we produce practically all our power in hydro form and even sell the excess to Sweden rather cheap.



happydolphin on 30 April 2012

Guys, this may seem like a dumb question, but:

If
"warming due to CO2 leads to more evaporation of water and more water vapor in general in the atmosphere, Water is a much stronger greenhouse gas than CO2 and can cause even more warming."
and we use hydrogen cars,
then wouldn't that pose a problem?



Kynes on 30 April 2012
happydolphin said:
Guys, this may seem like a dumb question, but:

If
"warming due to CO2 leads to more evaporation of water and more water vapor in general in the atmosphere, Water is a much stronger greenhouse gas than CO2 and can cause even more warming."
and we use hydrogen cards,
then wouldn't that pose a problem?


Climate, as any energy system, has positive feedbacks and negative feedbacks. If the positive feedbacks were stronger than the negative feedbacks, it would get out of control, and that's not what we have. It's more than probable that the clouds cool more than the greenhouse effect the H2O provides.



DarthVolod on 03 May 2012
thismeintiel said:
DarthVolod said:


We could go back and forth about how much of the scientific community supports climate change, and how much dissents. The fact that there are scientists dissenting fromt the theory in the numbers they are is rather telling when it is almost always in their financial and professional interest to support climate change theory even if they don't believe in it.

Playing devil's advocate though I can imagine that even if humans did have a significant impact on climate change there is really not much we can do about it. Countries like China are rapidly building up an infrastruction and an expansive manufacturing ecnonomy which puts out a massive amount of CO2 in the process all while while laughing at countries like America that shoot themselves in the foot with absurd regulations which kill industry while making them ever more reliant on foreign countries for basic goods.

Unless there is some sort of Orwellian all controlling world government put in place there is no way you are going to stop progress in every country. The good news for climate change supporters is that fossil fuels are finite so we will eventually have to find alternatives ... although I still believe there is a lot of coal around so that will be there for awhile.

 

What I find funny about man made Global Warming supporters is that, for the most part, they support people on the left, be they actors or politicians, because of there supposed passion about this subject and resolve to change things.  One has only to look at these peoples lifestyles to see that they don't truly believe what they are preaching about.  If they did, they would be dropping their own carbon footprint.  Instead they fly around on private jets.  Own multiple mansions that suck up electricity.  Own multiple expensive cars that are most likely horrible on gas mileage.  They're basically playing people for fools, asking you to change your lifestyle, persecute companies, while they continue to live lavishly.  And Al Gore is one of the worst offenders.


Lol you just reminded me of the enviromentalist group on my campus that is always passing around tons and tons of flyers. Even if the paper is recycled, 80% of them end up on the ground somehwhere which gets litter all over our otherwise clean campus which ironically makesthem the greatest polluters at my college.

The lifestyles of big supporters of global warming like Al Gore always reveal their true beliefs. I remember the big rich environmentalist types had a meeting on climate change in Copenhagen a few years back with attendees from around the world. Would it not be better for the environment to hold that same meeting online or through a conference call instead of burning thousands of gallons of jet fuel?



Rath on 03 May 2012
DarthVolod said:
thismeintiel said:

What I find funny about man made Global Warming supporters is that, for the most part, they support people on the left, be they actors or politicians, because of there supposed passion about this subject and resolve to change things.  One has only to look at these peoples lifestyles to see that they don't truly believe what they are preaching about.  If they did, they would be dropping their own carbon footprint.  Instead they fly around on private jets.  Own multiple mansions that suck up electricity.  Own multiple expensive cars that are most likely horrible on gas mileage.  They're basically playing people for fools, asking you to change your lifestyle, persecute companies, while they continue to live lavishly.  And Al Gore is one of the worst offenders.


Lol you just reminded me of the enviromentalist group on my campus that is always passing around tons and tons of flyers. Even if the paper is recycled, 80% of them end up on the ground somehwhere which gets litter all over our otherwise clean campus which ironically makesthem the greatest polluters at my college.

The lifestyles of big supporters of global warming like Al Gore always reveal their true beliefs. I remember the big rich environmentalist types had a meeting on climate change in Copenhagen a few years back with attendees from around the world. Would it not be better for the environment to hold that same meeting online or through a conference call instead of burning thousands of gallons of jet fuel?


Poor practices by supporters does not make the science poor.

In any case the amount of carbon contributed by the copenhagen conference is (relatively) miniscule. The amount of carbon that would not be produced if the world leaders actually got around to doing something about the problem would be huge.