My lecturer didnt agree with global warming. As he told that now we r in beginning of high sun activity period. Release of greenhouse gases (GHG) will increase temperature up to some extent. when temperature increases then lots of watervapours will goes up and that lead to formation of massive cloud.That cloud will prevent sunlight to come down to the earth then sudden cooling will occurs. He further said that role of could is not understood yet. Can some scholars discuss on this point. Thank you.
2007-11-12 11:12:06 · 9 answers · asked by PushUP 2 in Environment ➔ Global Warming
The climate is cooling. It hasn't been as warm as 1998.
That's 10 years without a warmer climate. And the cooling is increasing every year since then.
2007-11-12 14:36:55 · answer #1 · answered by Dr Jello 7 · 1⤊ 0⤋
With all due respect to your lecturer, I would hazard a guess that he isn't a climate scientist and, whilst undoubtedly an expert in his chosen field, probably isn't qualified to give factual advice about issues relating to climatology.
As a climatologist myself perhaps I can help shed some light on the points you riased...
<< As he told that now we r in beginning of high sun activity period. >>
No, at the moment we're in a trough of sun activity. The shortest solar cycle is the eleven year sunspot cycle and we're now in the lowest point. If these cycles were the cause of global warming we would have approx 5.5 years of warming followed by the same amount of cooling - quite clearly this isn't what happens. Looking further back in time the general trend in sun activity (total solar irradiance) in recent decades has been one of a slight decline. If global warming were down to the Sun we'd have had several decades of falling temperatures.
<< Release of greenhouse gases (GHG) will increase temperature up to some extent. when temperature increases then lots of watervapours will goes up and that lead to formation of massive cloud.That cloud will prevent sunlight to come down to the earth then sudden cooling will occurs. >>
Your lecturer is contradicting himself here. Originally he was saying he doesn't agree with global warming now he's saying that greenhouse gases cause temperatures to rise (that's precisely what global warming is).
Releasing GHG's, or more accuartely, increasing the atmopsheric concentrations of GHG's, will increase temperatures - of this there is no question as it comes down to nothing more than a simple physical property common to all the greenhouse gases.
It's quite true to say that as the temperature of the atmopshere increases it has the ability to retain greater amounts of water vapour (do a search for Dew Point and Saturation Vapor Pressure for more information about this). However, the increase is only a small one. Unlike the other greenhouse gases, the amount of water vapour the atmopshere can contain is determined by physical limits.
Water vapour is a very weak GHG but it is the most prevelant of all the GHG's and does contribute more to global warming than all the other GHG's combined.
What tends to happen when temperatures rise is that the water cycle accelerates, so whilst there's more water vapour entering the atmosphere it's also leaving it at a faster rate.
It's complicated to explain without going into detail but it's not correct to say it will lead to a massive formation of cloud. Think of a hot country, think of a cold country, which one has the most cloud? Chances are it was the cold country you thought of. So yes, higher temperatures leads to more water vapour but it also increases the threshold (SVP) at which clouds form.
<< He further said that role of could is not understood yet.>>
Climatology is a young science and is constantly evolving. We're learning as we go along and there are some things that aren't understood or aren't understood very well. There's something of a misconception regarding clouds and I think it may stem from the fact that the very early climate models didn't include clouds. Things have moved on since them and whilst we don't know everything there is to know about clouds we do know a lot about them. We certainly know enough to be able to assign an accurate range in respect of the role they play in global warming.
<< Can some scholars discuss on this point. Thank you. >>
You're welcome.
2007-11-12 16:18:07 · answer #2 · answered by Trevor 7 · 1⤊ 0⤋
Climate change is any long term change in Earth's average weather. It can result from both Earth's temperature warming and cooling. The current climate change is a result of a warming planet, which scientists believe to be caused by emissions of greenhouse gases by humans.
Your lecturer wasn't entirely right about the sun. While changes in solar activity certainly do have an effect on Earth's temperature, there hasn't been any trend in solar activity over the past forty years of sufficient magnitude to have caused the current warming.
Clouds are a major source of uncertainty in current climate models. While clouds do increase the planet's albedo (reflectivity), they also trap long wave radiation near Earth's surface. Scientists currently believe that clouds have a slight cooling effect, although it isn't enough to offset the warming. However, given the uncertainties involved, more research will have to be done before anything conclusive can be known. So, like Dana said above, your lecturer's confidence in his theory seems rather misplaced.
2007-11-12 11:34:09 · answer #3 · answered by SomeGuy 6 · 1⤊ 1⤋
It's true that cloud formation causes an overall cooling, and that the role of cloud formation in climate change is not well understood. Considering that information, it's hard to understand why your lecturer thinks he can conclude that clouds will cause an overall cooling effect in the future.
Most scientists agree that our increasing greenhouse gas emissions will overwhelm the much smaller cooling due to cloud formation, and the planet will continue to warm.
2007-11-12 11:20:57 · answer #4 · answered by Dana1981 7 · 3⤊ 2⤋
As much as people may give bitter argument to the fact, it is true that the earth has gone through warming and cooling cycles for millenia. For Man to come along and presume that there are global implications to his mere existence on this huge planet, is nothing more than arrogance. The earth has survived for billions of years, and will survive for billions more. NOTHING you and I can do will change the climate for better or worse. Gore is a politician. Keep that in mind when you hear his views...
2007-11-12 12:06:49 · answer #5 · answered by drunkandisorderly 3 · 1⤊ 1⤋
He's got his science completely wrong.
Solar radiation is decreasing:
"Recent oppositely directed trends in solar
climate forcings and the global mean surface
air temperature", Lockwood and Frolich (2007), Proc. R. Soc. A
doi:10.1098/rspa.2007.1880
http://www.pubs.royalsoc.ac.uk/media/proceedings_a/rspa20071880.pdf
News article at:
http://news.bbc.co.uk/1/hi/uk/6290228.stm
Clouds are a mixed bag. At night they hold heat in (you've surely noticed that clear nights are colder) and in daytime block sunlight. Likely those effects somewhat cancel and the overall effect of clouds is small.
But the increased water vapor that warmer air can hold will increase the greenhouse effect and the temperature.
He's a lecturer in what?
2007-11-12 11:25:23 · answer #6 · answered by Bob 7 · 1⤊ 2⤋
Scientist disagree on the subject of global warming. Your best bet is to listen to what your professor says, pass the test, but keep an open mind and read what other scientists have to say on the subject. Both the Weather Channel and National Geographic had good programs on this subject. No one is really sure 100%.
Certainly pollution is 100% fact - we CAN do something about that.
2007-11-12 11:18:37 · answer #7 · answered by J F 6 · 1⤊ 2⤋
Climate change is warming and cooling so the global warming people still have something to gripe about.
2007-11-12 13:34:48 · answer #8 · answered by enicolls25 3 · 1⤊ 1⤋
Ask Al Gore. he seems to have hyped it up to just about everyone and the stud press have bought it lock, stock and barrel.
2007-11-12 11:41:12 · answer #9 · answered by Anonymous · 2⤊ 2⤋