Meredith: Hi Kieran!

Kieran: Hi Meredith!

Meredith: your group members may be cramming work lol

Kieran: LOL

Meredith: since both need to :)

Meredith: ok

Meredith: which set did you look at?

Kieran: Urban Island, Greenhouse, Population

Meredith: ok

Meredith: one sec

Meredith: ok - so go ahead and explain what you found out

Kieran: CO2 levels have risen about 37% since the Industrial Revolution.

Meredith: wow

Meredith: 37% total?

Meredith: or 37% of something else?

Kieran: Yes. 104 ppm increase from 280 ppm pre-Industrial.

Kieran: CO2 is second largest constituent of greenhouse gases.

Meredith: ok

Kieran: Man-made are 5% of all CO2.

Meredith: ok

Meredith: so if that's so, how can CO2 cause a 37% increase

Meredith: just curious

Meredith: I'm looking into it now too, since your statement popped a new question into my head

Kieran: Over a 150 year period, it accumulates.

Meredith: ok

Meredith: so a 5% exponential growth curve. . . interesting

Kieran: That sounds right.

Meredith: ok

Meredith: keep going

Kieran: All greenhouse cases are rising, except CFC--probably due to legislation.

Meredith: ok

Meredith: and was there a clear correlation with GHGs and temperature increses?

Meredith: at least recent past?

Kieran: Yes, if you infer that the CO2 correlation with temperatures is similar to the other gases.

Kieran: Not necessarily causal, but the same trend.

Meredith: ok

Meredith: some web pages did factor analysis of GHG increases and GW. . . and gave a % effect

Meredith: did you see anything like that?

Meredith: just curious

Kieran: Do not recall.

Kieran: Can you enlighten me?

Meredith: ok - I saw some numbers last year placing GHG's role at about 40-60% of the current warming trend

Meredith: not sure how accurate, but a fair bit

Kieran: Thanks. That is interesting.

Meredith: just curious if you'd seen the same

Kieran: Do not remember. I focused more on the CO2.

Meredith: so GHG is a factor but part of a more complex set of causes?

Kieran: GHGs seem to have a paradoxical effect.

Meredith: what about the other ideas you looked into?

Meredith: oh - how so on the paradox?

Kieran: GHGs are necessary for warming (i.e., against abnormal cooling), but cause too much heat if in great supply.

Meredith: ok

Meredith: so the poison is in the dose

Kieran: The last thing about GHGs/CO2

Meredith: ok

Kieran: Sounds right.

Kieran: Respiration is responsible for 38% of CO2, but does not seem to include man among the animals responsible.

Kieran: ?

Meredith: right - mainly plants there

Meredith: although some animals

Meredith: if you take a photo of the earth from above, you see plants! lol

Meredith: so they really account for most of the respiration

Meredith: and photosynthesis of course . . . and all the critters in the oceans

Kieran: So, is respiration from man negligible even with increasing population?

Meredith: I would say we are a teenie tiny fraction

Kieran: O.K. Now, population...

Meredith: more bug mass in the world than human mass, I think

Kieran: wow!

Meredith: I'm pretty sure that's true . . . anyhow . . . well, don't quote me

Meredith: probably even more nematode mass than human mass for that matter

Kieran: 6.68 billion now. 5.8% of total ever born.

Meredith: again, don't quote me :)

Kieran: Thanks.

Meredith: right - lots of folks :)

Kieran: So, population would seem not to be a significant factor except as to how it relates to human activity.

Meredith: ok

Kieran: Urban Island...

Kieran: Anomalies (e.g., increases) seem more related to areas with surfaces and energy use than population or activity.

Meredith: ok

Kieran: They are looking into using different materials and colors in urban landscapes like white buildings, etc...

Meredith: ok

Kieran: So, in summary, it would seem as though GHGs/CO2 are the most likely factors in global warming.

Meredith: ok

Meredith: what did you find out about the ozone part?

Kieran: Not my part.

Meredith: ok

Meredith: well, I'll summarize the other sections

Meredith: in 10 minutes or less :)

Kieran: O.K.

Meredith: 1. ozone. . .

Meredith: there is a dramatic hole in the ozone layer

Meredith: in part due to the CFCs you mentioned

Meredith: and while those are on the decline, the hole persists

Meredith: may take time to fix or perhaps other causes

Meredith: the hole itself doesn't cause overall cooling or warming, but instead greater variations in temperature at the extreme poles

Meredith: or, so it seems

Kieran: Interesting.

Meredith: none of this is 100%, so that caveat follows through

Meredith: ok. .. so the hole. .. the hole increases and decreases based on season

Meredith: over each pole

Meredith: and in the summer I believe it is at its greatest size

Meredith: least size in the winter

Meredith: for each hemisphere

Kieran: hmmm

Meredith: so, it allows warm temps to get a bit warmer in summer, perhaps egging on melt

Meredith: which leads to the ocean currents . . .

Meredith: so, there is a pattern of water flow in the oceans called the thermohaline cycle

Kieran: O.K.

Meredith: since it is driven by both temperature and salinity

Meredith: cold salty waters in the north sink

Meredith: while warmer waters rise near the equator, etc.

Meredith: and this creates basically a convection cycle of sorts

Meredith: with an influx of fresh-water to the north from melt

Meredith: it is thought this cycle might slow

Kieran: O.K.

Meredith: and there is definitely a change in salinity that has been noted in the northern seas

Meredith: what a slow-down in this cycle would do is alter how the ocean currents redistribute heat around the globe

Meredith: so, bye-bye balmy Great Britain and Europe

Kieran: Wow.

Meredith: hello colder times . . . since those areas really rely on the jet streams and ocean currents to have warmer than normal temps for their latitude

Meredith: latitude

Meredith: so, not a cause of warming, but perhaps an effect

Meredith: and lastly solar variation

Meredith: the sun goes through small 11-year cycles of activity maxima and minima

Meredith: which does influence temps on the planets some

Meredith: up until the modern era, data really showed that solar variation influenced global temp changes about as much an anything else

Meredith: there are also longer cycles and of course other contributing factors that caused the cycle or ice ages, etc as well

Meredith: but we are in a solar maximum by many accounts

Meredith: and have been for a while . . . this may be contributing to as little as 15% of the current warming to as much as 30%

Meredith: but still not the major factor

Meredith: and not much we can do about it lol

Meredith: was that 10 min or less?

Meredith: lol

Meredith: tried to

Meredith: anyhow

Meredith: hopefully the idea that this is all pretty complex became more clear than before

Kieran: Nice :-)

Meredith: although I'm sure you realized that already

Meredith: so, next week there will be a final set of things to look into

Meredith: and since the other groups were cut short

Meredith: no need to make you do what the others didn't have to in terms of brainstorming

Meredith: I'll just post what is already put together

Meredith: clearly there is one variable that we can do anything about related to GW

Meredith: which is the human side of things

Meredith: so the last week looks into details related to that

Kieran: Sounds good.

Meredith: and like before, just choose the part you find interesting, and I'll be around to fill in if others don't show up

Meredith: you have a good week and good luck finishing up

Kieran: O.K.

Kieran: You also.

Kieran: Ciao, Meredith :-)

Meredith: bye!