If you google "tropical deep convection" or "hurricane dynamics" you can get some details on what I mean when I say that humidity is a form of energy, and how the energy released through condensation can drive weather.
gcnp58 covered part of what I was thinking of adding, latent heat, evaporation, and condensation. Bear in mind that water stays in the atmosphere only for a short time. When it leaves as condensation, it releases into the air large amounts of sensible heat. The oceans cover 71% of the earth's surface and have an average albedo of only 7% to 10%, so they absorb a lot of heat energy in the top surface layer, which feeds the evaporation. The oceans gather energy from the sun, transfer that energy into latent heat in water vapor in the air, which then condenses depositing that latent heat energy into the air -- the effect is a transfer of ocean absorbed heat into atmospheric heat and that itself only in localized areas where the condensations occur. So there are differentials between those areas and other local areas and these differentials lead to wind vectors.
Interestingly, hurricanes are engines that transfer heat energy from the earth's surface layers upwards towards the stratosphere. If you look at the surface sea temperature (SST) maps just after a hurricane has passed by, you can see the cooler SST trail it leaves there. Hurricanes help the earth lose energy back into space because heat transferred upwards into the stratosphere has less remaining atmosphere to block its eventual release into space, so more of the heat energy deposited that high (which radiates in all directions) makes it outward into space and less of it back to Earth again. Hurricanes are a negative feedback mechanism of sorts, helping the earth remove a small part of otherwise retained heat energy.
But I wanted to also take a clue from your question and be a little more direct there. Dr. Jennifer Francis has recently been discussing some of her work studying the impacts of the changes around the north pole on the jet stream and the implications of this kind of climate change on weather for North America. You could look her name up and see one of several youtube videos talking about this. A few years ago, I believe, she predicted significant weakening of the jet stream and, consequently, much more north-south meandering and that weather will probably "stick around" longer, creating extended durations for weather conditions. Extended dry spells in some areas, extended cold or extended heat in others, etc. Those also create "extreme weather" events.
See the two links below for more information here. The first is more for general audiences, the second is more for weather geeks, I think.
>>. If the poles warm up faster than the equator, this lowers the temperature differential world wide. Therefore lowering the risk of extreme weather.<<
That may reduce the overall number of storms, but increase the number of severe storms. Increased atmospheric moisture provides more fuel for storms. Combined with increasing temperatures this creates the potential for more severe storms and cycles of storm events.
>>I understand that higher temperatures will increase humidity world wide, but without the large difference in air temperature, this just means more rain.<<
But that increased humidity also comes at the expense of removing soil moisture and precipitation is not evenly distributed. This results in arid regions facing the risk of even dryer conditions and regions already susceptible to floods becoming even more vulnertable.
Simple answer it doesn't, and the fact that we have had no warming for the last 16yrs, so how can extreme weather be down to warming, and statistically it is not true, and anyway extreme weather is the result of temperature difference between the atmosphere and the surface, most notably the oceans. with warming the temperature difference is less, as oceans warm up slower.
We have extreme weather reporting, and costs due to weather have skyrocketed, but that's a different matter.
A lot of it is simply due to melting glaciers.
The first issue is that there would be less albedo (glaciers reflect sunlight). This would accelerate the effects of global warming, since many glaciers also store compounds like methane (CH4) within them. Their melting would release this, causing a positive feedback loop.
The melting of glaciers would also raise water levels as well, which would severely impact many coastal regions like the Florida keys.
Without a doubt the most devastating impact would be the fact that melting glaciers ultimately leads to a changing of currents in the ocean, including underwater currents. This would change climate on an international level, and change the way sediments are distributed within the ocean. This coupled with water temperature changing would lead to an increase in tropical storms like hurricanes.
Mass migrations. As temperatures change, many insects like butterflies migrate north to find cooler areas to live in. Diseases vectors (which are usually most common around the equator) would spread north and south as well, which would increase the range of diseases like malaria. Of course mass migrations aren't limited to just butterflies and disease vectors like mosquitos, but I'm sure you get the idea. This would also disrupt many tropical ecosystems.
As with floods being more common, so are droughts. Ocean currents are responsible for many climates, so if you can put one and one together, many regions on earth would have vastly different climates. Some would be more wet, others would be devastated by drought. This drought would also be exacerbated by the fact that global temperatures would have risen as well.
Because of there have formed many industries and there have had been air pollution. so that oz-en layer is depleted.
**disclaimer** Everybody please. This is not a discussion of the validity of global warming. I do not care about your politics or beliefs. And I don't care what you think about my beliefs. Because they are irrelevant. If you feel the urge to express your opinion, tell me on twitter or something.
I have read many news articles in recent years about how global warming will increase extreme weather events. But I don't understand why. If the poles warm up faster than the equator, this lowers the temperature differential world wide. Therefore lowering the risk of extreme weather.
I understand that higher temperatures will increase humidity world wide, but without the large difference in air temperature, this just means more rain. I also understand that air and sea currents could change dramatically compared to what we are currently used to. And this can be disastrous to certain local weather systems. But that doesn't extrapolate world wide.
So does any out there have a clear understanding of this? Or is it just the media, cherry picking the "disaster" headlines.
