Climate change and the global hydrological cycle

One of our pals has shown a gross level of misunderstanding regarding how warming our global climate system will alter fundamental aspects of the world hydrological cycle in ways that are sure to be detrimental to prosperous farming and other modern pursuits our society depends on.

In truth it is a heck of a lot easier to grow all kinds of food in hot and steamy Alabama than cold and snowy Alberta. No shit Sherlock, warmth is more conducive to life than cold as long as there is water. Considering that precipitation comes from evaporation, and evaporation increases with temperature, then it stands to reason that global precipitation will increase with global warming. Hotter and wetter means a whole lot more agricultural productivity. How this situation looks like doomsday to you is truly baffling to me.
I believe his nonsense deserves to be called out with solid information that will help folks better grasp what's going on out there.
Climate Change Has Intensified the Global Water Cycle Published: April 26th, 2012 By Michael D. Lemonick http://www.climatecentral.org/news/climate-change-has-intensified-the-global-water-cycle Climate scientists have been saying for years that one of the many downsides of a warming planet is that both droughts and torrential rains are both likely to get worse. That’s what climate models predict, and that’s what observers have noted, most recently in the IPCC’s report on extreme weather], released last month. It makes physical sense, too. A warmer atmosphere can absorb more water vapor, and what goes up must come down — and thanks to prevailing winds, it won’t come down in the same place. The idea of changes to the so-called hydrologic cycle, in short, hangs together pretty well. According to a new paper just published in Science, however, the picture is flawed in one important and disturbing way. Based on measurements gathered around the world from 1950-2000, a team of researchers from Australia and the U.S. has concluded that the hydrologic cycle is indeed changing. Wet areas are getting wetter and dry areas are getting drier. But it’s happening about twice as fast as anyone thought, and that could mean big trouble for places like Australia, which has already been experiencing crushing drought in recent years. The reason for this disconnect between expectation and reality is that the easiest place to collect rainfall data is on land, where scientists and rain gauges are located. About 71 percent of the world is covered in ocean, however. “Most of the action, however, takes place over the sea," lead author Paul Durack, a postdoctoral fellow at Lawrence Livermore National Laboratory … The climate models weren’t really wrong, Durack hastened to add. “They’re accurately capturing the spatial patterns in hydrologic changes, and they’ve got the basic physics right. They’re just providing very conservative estimates of how big the changes are, and now we’re starting to understand that." …
Climate change and the hydrological cycle BY YOCHANAN KUSHNIR|DECEMBER 19, 2008 http://blogs.ei.columbia.edu/2008/12/19/climate-change-and-the-hydrological-cycle/ The prospects of significant and damaging changes in the hydrological cycle due to the increase in atmospheric greenhouse gas concentrations were raised in earlier IPCC reports and restated more strongly in the most recent, 2007 Fourth Assessment Report (AR4). Now, the U.S. Climate Change Science Program (CCSP) issued its final Synthesis and Assessment Report on Abrupt Climate Change with an entire chapter dedicated to the subject of “Hydrological Variability and Change" addressing this potential climate hazard. Overall, the chapter confirms the IPCC AR4 conclusions giving an extensive survey of the history of U.S. droughts and the physical mechanism behind their occurrence. Here we highlight a few points regarding the major conclusions stated in the CCSP Report. 1. Two types of drought: … 2. How does global warming cause subtropical drying? To understand the mechanism of greenhouse warming related droughts we note that regionally, the hydrological cycle is a balance between two large terms: the atmospheric moisture influx into the region and the local difference between precipitation and evaporation (two smaller terms: storage of moisture in the upper ocean or in the ground and runoff of surface water in streams and rivers, complete the balance). Much of the subtropics lie over the world ocean areas where climate models indicate that when greenhouse gas concentrations increase and the surface warms “dry" regions, from which the atmosphere extracts moisture, will experience increased drying while “wet" regions, where atmospheric moisture inflow allows precipitation to exceed evaporation, will get wetter. This is a direct result of the warmer atmosphere being able to hold more moisture and thus existing patterns of atmospheric moisture transport intensify. Since currently the atmosphere exports moisture out of the subtropics and evaporation in these areas exceeds precipitation, this imbalance will increase in the future, drying these belts even further. Over land the situation is somewhat different. … 3. Future droughts and “natural" climate variability. ... 4. How certain are these projections? ...
Global Warming May Alter Critical Atmospheric Rivers How will climate change impact the source of much of California's water? By Andrea Thompson, Climate Central on February 6, 2015 http://www.scientificamerican.com/article/global-warming-may-alter-critical-atmospheric-rivers/ The hose has been turned back on full-force over Northern California: A stream of moisture is flowing over the drought-riddled state and dropping copious amounts of rain just days after the close of one of the driest Januaries on record. The influx of much-needed rain comes courtesy of a feature called an atmospheric river that is a key source of much of the state’s precipitation and water supply. A relatively recent meteorological discovery, these ribbons of water vapor in the sky are something scientists are trying to better understand. …
CCSP - SAP 3.4 Abrupt Climate Change Report Chapter 2 Hydrological Variability and Change Chapter Lead Author: Edward R. Cook,* Columbia Univ., Palisades, NY Contributing Authors: Patrick J. Bartlein,* Univ. OR, Eugene; Noah Diffenbaugh, Purdue Univ., West Lafayette, IN; Richard Seager,* Columbia Univ., Palisades,NY; Bryan N. Shuman, Univ. MN, Minneapolis; Robert S. Webb,* NOAA, Boulder, CO; John W. Williams, Univ. CA Santa Barbara; Connie Woodhouse, Univ. AZ, Tucson. Key Findings Variations in water supply in general, and protracted droughts in particular, are arguably the greatest natural hazards facing the United States and the globe today and in the foreseeable future. In contrast to floods, which reflect both antecedent conditions and current meteorological events, and which are consequently more localized in time and space, droughts occur on subcontinental to continental scales, and can persist for decades and even centuries. On interannual to decadal time scales, droughts can develop faster than the time scale needed for human societies to adapt to the change. Thus, a severe drought lasting several years can be regarded as an abrupt change, although it may not reflect a permanent change of state of the climate system. … These megadroughts are significant, because they occurred in a climate system that was not being perturbed by major changes in its boundary conditions anthropogenic changes in greenhouse gas concentrations, atmospheric dust loadings, and land-cover changes). ...
Also, global warming is likely to increase precipitation, but not everywhere. Changing weather patterns could increase drought in some regions. Present crops each have their optimal temperature range. For example, development of winter wheat was good for cold climates, but not so good for warm climates. Fortunately we already have a lot of experience with tropical agriculture. Yields are increasing dramatically in tropical countries and American farmers will have no problem obtaining and planting varieties that thrive in climates just a few degrees warmer than present.
We shouldn't forget that our weather patterns are an interplay between the hot tropics and the Arctic and Antarctic - three fundamentally different regions of our globe. The equator, as though on a spit, roasting under the nonstop intensive radiant heat of the sun. As for the poles, they are opposites. The Arctic is an ocean surrounded by continent and the Antarctic is a continent surrounded by ocean. Whereas the Antarctic is the major driver of ocean currents, the Arctic is the major driver of Northern Hemisphere weather through it's interaction with the atmosphere and Jet Streams. Something that is undergoing a radical change. You see over the poles you have this mass of frigid air and around the belly of our planet we have hot air flowing towards the two poles. The jet streams are the zones in-between that form a boundary, as they race around our globe. Think about it, when I was a kid the Arctic was still pretty much solid ice. That glaring ice reflected the sun's ultraviolet rays right back into space, out and away from our global climate system.) This Ice Cap also isolated ocean currents away from the atmosphere, which had profound meteorological and ocean circulation consequences. Impacts that dictated the way our weather patterns operated. Consider increasing portions, major portions of Arctic Ice Cap has disappeared, removing that lid, so to speak. What does that mean? For starters the exposed ocean now acts as a solar collector capturing those ultraviolet rays and converting them to infrared radiation and heat that becomes part of our global climate system. ~ This in turn is causing water molecules to break free from the ocean and rise into the atmosphere. Turns out to be rather massive amounts of water vapor entering the Arctic Circle's atmosphere in a way that hasn't occurred in millions of years. While all this is going on the temperature gradient between the equator and the rapidly warming North Pole has lessened, causing the Jet Stream (That pusher and puller of storm systems.) to meander more and more, (Sort of like a river coming out of the foot hills and onto the plains.). This can't help but result in all sorts of upheaval to the weather patterns Earth has been experiencing between >1850 and 2010. Our changes to the system are new, and the major results are in the pipeline. Simple geophysics in action - it's just how it is no matter how much derision some fling at it. https://globaloffshorewind.wordpress.com http://www.skepticalscience.com/news.php?f=jetstream-guide

Okay, here’s the meat and potatoes. dusty, it’s not just my imagination :coolsmirk:

Rough Guide to the Jet Stream: what it is, how it works and how it is responding to enhanced Arctic warming Posted on 22 May 2013 by John Mason http://www.skepticalscience.com/news.php?f=jetstream-guide Barely a week goes by these days in the Northern Hemisphere without the jet stream being mentioned in the news, but rarely do such news items explain in detail what it is and why it is important. As a severe weather photographer this past 10+ years, an activity which requires successful DIY forecasting, I've had to develop an appreciation into what makes it tick. This post, then, is a start-from-scratch primer based on that knowledge plus some valuable assistance from academia into where the current research is heading. Because of its length and breadth of coverage, I've broken it up into bookmarked sections for easy reference: to come back here click on 'back to contents' in each instance. Contents: Earth's Troposphere - an introduction Weather systems aloft - the Polar Front and the jet stream Waves on the jet stream - upper ridges and troughs Positive vorticity - a driver of severe weather - and the jet stream Wind-shear - a driver of severe weather - and the jet stream Jetstreak development along the jet stream - a driver of severe weather Northern Hemisphere atmospheric circulation patterns: the Arctic and North Atlantic Oscillations Climate change and the future: how will the jet steam and pressure-patterns respond? Conclusion
It's worth learning about.
Arctic Amplification w/ Jennifer Francis, June 2013 Published on Jan 9, 2014 https://www.youtube.com/watch?v=SxMNGTMYMfM Great overview on the leading thinking behind why the Earth's weather system is changing rapidly before our eyes. What happens in the Arctic system happens to the rest of the globe. It's all one large system. As the temperature gradients continue to weaken between the high and mid latitudes, the jet stream is stalling and become more relaxed.
Recent Changes in Blocking Characteristics Assessed Using Self-Organizing Maps Speaker: Jennifer Ann Francis | Published on Dec 19, 2015 https://www.youtube.com/watch?v=11G2XyGm-DU Blocking anticyclones are known to be associated with persistent weather patterns that often lead to extreme weather events. An outstanding question, however, is whether the frequency and/or intensity of these dynamical features are changing in response to human-caused climate change, and in particular, to a disproportionately warming Arctic. In this presentation we describe a study using a pattern-recognition/clustering tool called Self-Organizing Maps (SOMs) to investigate the temporal behavior of blocks over recent decades, and attribute any changes to either frequency shifts in characteristic atmospheric patterns or to cluster-mean changes in a blocking characteristic for a given pattern. In this application, we use single contours of 500-hPa heights from reanalyses to identify characteristic ridge/trough patterns in the upper-level flow in the northern hemisphere.