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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Recommended supplemental reading:

Global Warming Hole by James Hansen, Mar 31, 2015

Maaark at 06:07 AM on 1 April 2015

Heat from the Earth’s interior does not control climate

The hypothesis of earth core heat affecting sea temperature and atmosphere should be taken more seriously. NASA takes it seriously enough to research it. Here is a link to their 2011 study which shows significant correlation but inconclusive in the end. Maybe the variable to consider is not overall increased heat but movement of the heat source which changes exposure to different areas.

http://climate.nasa.gov/news/489/

wili at 05:03 AM on 1 April 2015

Sea Level Rise is Spiking Sharply

From the description under the first figure: "...may signal the drying out of the major continental basins in the tropics."
Is this really the only likely explanation? Don't we expect an acceleration in slr at some point from increasing losses from GIS and WAIS among others? Haven't we been hearing more about further evidence of destabilization of both? How would we know if increase loss from these source are or are not part of the cause of the recent increase in the rate of slr?

GFW at 05:02 AM on 1 April 2015

Global warming and drought are turning the Golden State brown
One suggestion that would greatly improve the ability of that scatter plot to convey information: Color code the dots along a spectrum from the earliest year to the latest year. That way it's obvious at a glance if there is an overall trend.

jja at 03:50 AM on 1 April 2015

Global warming and drought are turning the Golden State brown

one planet @4

The temperature effects that the earth is experiencing today is at the emissions levels from 2005. This is without considering the substantial dimming and albedo effects of short-lived anthropogeic aerosols. If you include those factors the earth system response may well be operating at forcing values consistent with 1994 levels, when Russia had its emissions slowdown.
It is extremely unlikely that, in the face of rapid 'catch-up' of recent emisisons increases and the reduction of chinese aerosols due to economic cycles and pollution mitigation efforts, that the Summer Arctic Sea ice will last the next 10 years.
This will produce a significant northern push of the Hadley Cell and exacerbate the perpetual drought that the U.S. southwest has experienced these last 15 years.

For more info see: http://www.latimes.com/science/sciencenow/la-sci-sn-climate-drought-california-20150223-story.html

Moderator Response:

[JH] Link activated.

Stephen Baines at 02:05 AM on 1 April 2015

Sea Level Rise is Spiking Sharply

Technically speaking, we are in an El Nino now, albeit a very weak one. So it may not come down top whether an El Nino develops, but whether this one persists and intensifies.

Interestingly almost all of the statistical models reviewed by NOAA are predicting a shift to neutral conditions, whereas most of the more mechanistic models are predicting a strengthening of the El Nino.

PhilippeChantreau at 01:06 AM on 1 April 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog, the statement with which I have a problem has been clearly established. You made it in post# 9 above. You exact words were: "Arctic Climate is relatively stable from 2005 to today." Such a statement is not a matter of opinion. It can be made only if supported by data. By the same token, how many years are necessary to establish a significant trend with that data is not a matter of opinion either. That's why I'm asking. You say the longer the better, so 10 years seems to not meet your own preference.

In post #20 you made a bold statement with an exclamation point: "Antarctica's Land Ice Mass is Growing!" It is impossible to honestly not construe that this means the whole of Antarctica's land based ice mass.

You supported that statement with Memin et al, 2014. Two other contributors above quoted the conclusion section of the paper, which I re-quote here:"Comparing our mass-balance budget with that from King et al. (2012) for AIS regions not covered by Envisat, we obtained that the AIS lost −47±35 Gt/yr in good agreement with recent published results and validating our methodology." I do not see how one can use this paper to make the bold statement you made in post #20, while there is a weight of evidence pointing to negative mass balance for the whole continent. You diverted attention from that fact by pointing at regional changes, as there are unfortunately no squirrels to point toward in Antarctica.

The NASA article in which you quoted the uncertainty about land based ice mass balance is dated from 1999. How much research has since been published on the subject?

You said in post # 20 that one should consider the overall, two-hemispheres ice volume. It is not entirely clear whether this applied to sea ice or land based ice. Ice volume is not the best metric for land based ice sheets, whose mass is usually the object of study and gives a much better idea of the true quantity present. So I assume that you meant sea ice volume. Unlike land ice, sea ice does not undergo compression over the years, but its thickness greatly affects the true quantity present, so volume really is the best metric, you were right on that.

DSL cited 3 papers that are sea ice volume studies, showing that the Arctic loss is about an order of magnitude greater. That's a factor of 1000, not exactly benign. You responded by a comparison of sea ice area numbers, in contradiction with your own claim earlier that ice volume should be considered.

I'll make the mother of all understatements by saying I'm not impressed.

DSL at 00:27 AM on 1 April 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

My final comment should have read as follows:

As you can see, the positive winter trend over the satellite period (35 years) in the Antarctic is half of what the negative winter trend is in the Arctic. The Antarctic summer trend, also positive, is 8x less than the negative Arctic summer trend.

KR at 00:24 AM on 1 April 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog - Total Antarctic mass balance is negative, declining, and all the evidence points to that loss accelerating. The Memin paper you've referenced is discussing snow and ice height, not mass balance (only one side of the equation), and certainly is not in contradiction to other estimates of mass loss. It's very very certain that Arctic, Antarctic, and Greenland ice sheets are diminishing, despite your misinterpretation of htat paper.

You've presented some factoids (somewhat smaller than a fact, due to lack of context) regarding Antarctic ice. What your numbers neglect is seasonal variation - when looking at longer term climate change you need to look at trends in anomalies, in change. For example, here's some data charted (and discussed by) Tamino:

[Seasonal cycle removed - Source]

As is quite clear, the increase in the Antarctic is considerably less than the decrease in the Arctic.

Over on RealClimate there's a very good discussion of Antarctic sea ice, it's effect on climate, and the very different causes of ice changes there as compared to the Arctic. I would suggest you read it. The take-home point is that while counter-intuitive, those changes are themselves due to climate change.

DSL at 00:23 AM on 1 April 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Shorter Watchdog:

Ice mass is increasing in some places and decreasing in other places. I'm not willing to do the math, and I'm going to ignore comprehensive analyses such as Shepherd et al. 2012.

Your comparison of sea ice area is irrelevant or a red herring with regards to your earlier comments about volume--which I addressed. Area is not volume.

Antarctic sea ice increases by about 13 million km2 each SH winter (not 16 m km2). You'll note from the same link that it decreases by about the same amount each SH summer. The area anomalies within the last few years have almost cancelled out, but, again, over the last 35 years, the Arctic has lost much more area than the Antarctic has gained.

The greatest Antarctic winter maximum area for the satellite period (up through 2013 — I haven't updated my data) is 16.232 km2 (2007). The lowest max in the period is 14.604 million km2 (1986). The linear trend for the period is +19,926 km2 per year. The difference between the two is 1.628 million km2.

The greatest summer minimum in area is 2.473 million km2 (2003). The lowest summer minimum is 1.296 million km2 (1993). The difference between the two is 1.177 million km2. The linear trend for the period is +8965 km2.

The greatest Arctic winter maximum area for the satellite period (up through 2014) is 15.01 million km2. The lowest max in the period is 13.04 million km2. The linear trend for the period is -38,213 km2. The difference between the two is 1.97 million km2.

The greatest summer minimum in area is 5.59 million km2. The lowest summer minimum is 2.28 million km2. The difference between the two is 3.31 million km2. The linear trend for the period is -70,309 km2.

As you can see, winter gain over the satellite period (35 years) in the Antarctic is half of what winter loss is in the Arctic. Antarctic summer gain is 8x less than Arctic summer loss.

PhilippeChantreau at 00:13 AM on 1 April 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog, you are not answering any of my 2 questions. You made the assertion that Arctic climate was stable over the past 10 years. I'm asking you on what time series you are basing this claim and, for the time series considered, how many years of data are necessary to establish a statistically significant trend.

Stephan at 00:11 AM on 1 April 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Re. 20, Watchdog: That seems to be a very selective reading of "Snow- and ice-height change in Antarctica from satellite gravimetry and altimetry data". From the conclusion of the paper: "Comparing our mass-balance budget with that from King et al. (2012) for AIS regions not covered by Envisat, we obtained that the AIS lost −47±35 Gt/yr in good agreement with recent published results and validating our methodology."

So while there are some areas where snow accumulation is contributing to ice mass, overall the balance is significantly negative.

witsend at 00:01 AM on 1 April 2015

The cause of the greatest mass-extinctions of all? Pollution (Part 2)

A well-known effect of pollution exposure on plants is increased insect activity. Vegetation loses natural immunity as it becomes weakened from repairing the damage from absorbing ozone and it also is caustic, eating away at protective way coating on leaves, opening the way to biotic attacks. Apparently, this occurred during the PETM extinction: http://www.pnas.org/content/105/6/1960.short

One Planet Only Forever at 23:13 PM on 31 March 2015

Global warming and drought are turning the Golden State brown

saileshrao,

Reviewing the chart plot of all the years shows 2014 to be a dramatic change from 2012 and 2011. And 2013 is not even at the fringes of data points in the Dry, Hot quadrent.

If the global warming is kept to levels below 2 C then these drought events will still happen, and be more frequent or more extreme or longer lasting, but they will not be an almost permanent condition of drought that varies from "Very Dry and Hot" to "Never previously experienced Dryness and Heat".

Watchdog at 22:41 PM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

DSL - Mamin et al 2014 - Ice mass in EAIS and ice and snow in other areas of Antarctica is increasing. Ice mass in the smaller WAIS is decreasing. https://www.deepdyve.com/lp/elsevier/snow-and-ice-height-change-in-antarctica-from-satellite-gravimetry-and-M7Kh2pubyn

Comparison of Arctic & Antarctic Sea Ice areas.

• Annual averaged arctic sea ice area = c.7.5 million km2

• From Feb 2012 to Sept 2013 Antarctic sea ice grew c.16 million km2.

• "Since the start of the satellite record, total Antarctic sea ice has increased by about 1 percent per decade." — NASA
http://earthobservatory.nasa.gov/Features/WorldOfChange/sea_ice_south.php

Phillippe, In spite of the fact that the IPCC chose to consider 30 years of data as being sufficient to establish certain claims upon today and our future, since you asked me, when it comes to me examining any Climate Change, the longer time periods to examine, the better; before my arriving at any determination concerning today's climate and beyond.

IMO - Just because Arctic sea ice is what it is (sea ice sans land ice), is that any reason to exclude the entire reverse-to-arctic fluctuating volume of ice in the Southern polar region whilst performing Climatic calculations - as if - the fluctuation and/or trend of Arctic "sea ice" is - unto itself - an accurate measure of Global Climate?

Moderator Response:

[JH] You continue to skate on the thin ice of escessive repititon and your "throw-it-against-the-wall-to-see-what-sticks" modus operandi is wearing very thin.

To reiterate, posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

saileshrao at 22:24 PM on 31 March 2015

Global warming and drought are turning the Golden State brown

"The good news, however, is that this is only one possible future. If society works to limit global warming to under 2 °C, which is still possible (1), then we can likely avoid committing to a brown California."

If California is experiencing such a drought with global warming at a mere 0.8 °C, how is this "good news" assertion justified?

CBDunkerson at 21:33 PM on 31 March 2015

Ipso proves impotent at curbing the Mail's climate misinformation

ryland, so how exactly would you suggest they go about showing a photograph of the actual emission of CO2 from power plants? Given that CO2 isn't visible?

Sorry, but I'm just not buying it. There is nothing 'false' about showing power plants as a source of the CO2 which causes global warming.

Which illustrates to a degree the problem that IPSO and other 'press scrutiny' organizations face... people live in very different realities and what is 'truth' for one person is very often 'fiction' for another. That said, there are objective truths that these organizations could and should enforce. Whether or not some people might mistake visible steam for invisible CO2 and thereby be 'deceived' into a 'reinforced message' that power plants cause global warming (which... they do) is exceedingly subjective. The fact that arctic sea ice is on a declining trend is not.

uncletimrob at 18:55 PM on 31 March 2015

Global warming and drought are turning the Golden State brown

I like the cold/hot/dry/wet graph! A nice representation that says much. Thanks.

ryland at 14:50 PM on 31 March 2015

Ipso proves impotent at curbing the Mail's climate misinformation

CB Dunkerson My point about the steam from cooling towers is that these pictures are juxtaposed to stories about global warming due to human emission of CO2 from burning fossil fuels. The picture gives the impression that this is an example of the pollution due to this burning when in fac t it is nothing of the kind. The picture is falsely used to reinforce the message of the written piece.

DSL at 14:28 PM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Also, Watchdog, where is your data source for the following claim: "The Growing Antarctic Ice Phase during the Southern Hemisphere's Semi-Annual Climate Cooling ICE Growth Phase outstrips the much smaller in Volume simultaneous occurring of Arctic Sea Ice Shrinkage."

One thing you need to consider when comparing volume: Arctic sea ice thickness has been much greater than Antarctic sea ice thickness. Meters-thick multi-year ice once dominated the Arctic. Most of that has been lost over the last 35 years. Antarctic sea ice, in contrast, has mostly melted out each SH summer. This has led Kurtz & Markus 2012 to conclude that "These results [of little change in Antarctic sea ice volume] are in stark contrast to the much greater observed losses in Arctic sea ice volume and illustrate the different hemispheric changes of the polar sea ice covers in recent years."

Massonnet et al. 2013, using a model-assisted reconstruction, find that "the global Antarctic sea ice volume has risen at a pace of 355 +/-338 km3/decade (5.6 +/- 5.3%/decade) during [1980-2008]." You can see from PIOMAS that Arctic volume loss over the same period dwarfs that estimate (to the tune of 3000 km3/decade +/- 1000 km3).

Holland et al. 2014 agrees with Massonnet, concluding this: "This ice volume increase is an order of magnitude smaller than the Arctic decrease, and about half the size of the increased freshwater supply from the Antarctic Ice Sheet."

Perhaps you have other sources. I will continue to look for evidence that supports your position in the literature, but I am not hopeful.

Stephen Baines at 14:07 PM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog

That NASA text looks to be old as it refers to laser altimetry satellite data in the future tense, even though ICEsat went up in 2003. At that time it's safe to say the issue was up for debate. Now less so.

Second, the reference you claim estimates ice mass loss (Memin etal 2014. Earth and Planetary Science Letters 404: 344–353.) says this in it's conclusions.

"Comparing our mass-balance budget with that from King et al. (2012) for AIS regions not covered by Envisat, we obtained that the AIS lost
−47 ± 35 Gt/yr in good agreement with recent published results
and validating our methodology."

You might be confused by the sign on the mass loss (loss of a negative number is a positive?), but a quick look at their table 1 shows that they are in rough agreement with all the other studies that have used gravimetric and altimeter information to show there has been mass loss from Antarctica.

DSL at 14:05 PM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog, I'm not seeing where in Memin et al. 2014 you found that the overall ice mass in Antarctica was growing. Table 1 strongly suggests that a positive overall trend is unlikely at best, and the authors never actually state their assessment of overall mass balance or contradict the overall mass balance assessments of others.

Also, your first link--to NASA--is weak. It was written sixteen years ago.

Rob Honeycutt at 13:52 PM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog... Regarding your first link, you sorta kinda need to read the whole thing to get the gist of what they're discussing. Later in that passage on the Earth Observatory they state:

In addition to increasing the amount of melting, global warming would also be expected to increase the amount of precipitation in the polar regions. There are three reasons for this: 1) warmer air can carry more moisture than colder air; 2) warmer wates would encourage increased evaporation from the ocean; and 3) lessened sea ice would also lead to more evaporation from the ocean, as more ocean area would be exposed directly to the atmosphere. Global warming could therefore be expected initially to increase both melting and snowfall. Depending on which increase dominates, the early result could be either an overall decay or an overall growth of the ice sheets.

PhilippeChantreau at 13:16 PM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog, that is a rather surprising response. Not only the period to determine what is climate shows up all over the IPCC as 30 years, but there is also a limit as to how much data you need to establish a trend, or lack thereof. Since you ask, I'll redicrect the question to you. What time series are you considering to make your assertion? How many years of data are necessary to establish a statistically significant trend for said timeseries?

Watchdog at 10:27 AM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Stephen Baines,

NASA concluded that it is uncertain whether or not Antarctic & Greenland's Land Ice is increasing or decreasing; and I quote:

"It is uncertain, however, whether the world's two major ice sheets-Greenland and Antarctica-have been growing or diminishing."
http://earthobservatory.nasa.gov/Features/PolarIce/polar_ice2.php

AND and, a paper in Earth & Planetary Science Letters is more specific: Antarctica's Land Ice Mass is Growing!

The data examined shows most areas of the ice sheet are stable to increasing in ice mass, including the East Antarctic ice sheet, which alone contains over 80% of the total ice mass of Antarctica.

Snow- and ice-height change in Antarctica from satellite gravimetry and altimetry data -- published Oct 15, 2014
http://www.sciencedirect.com/science/article/pii/S0012821X14005068

+
My point continues to be:

One should include both Northern & Southern Hemispheric ICE ice Data (aka Global ICE Volumes at any given Time), IF/WHEN if/when one is presenting -> ICE ice Affects upon the Globe.

Moderator Response:

[JH] You are now skating on the thin ice of excessive repition which is prohibited by the SkS Comments Policy. In addition, the use of "all caps" is akin to shouting and is also prohibited by the Comments Policy.

Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

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Stephen Baines at 08:35 AM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Here is another paper indicating effects of glacial melting on sea ice production.

Stephen Baines at 08:22 AM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog,

Tristan is referring to land ice on Antarctica, which is losing mass just as it is in Greenland. Loss of land ice definitely suggests there is melting due to a warming of the climate in both hemispheres.

The extent of sea ice in Antarctica is not only influenced by temperature, which has actually been increasing for both surface ocean and air in the Southern Ocean. Winds that blow ice out to sea in winter, and decreasing salinity, which is negatively affected by ice cap melt, both increase winter maxima in sea ice extent of Antarctica.

chrismc at 06:31 AM on 31 March 2015

Ipso proves impotent at curbing the Mail's climate misinformation

Now that the General Election is officially underway in the UK, expect more of this sort of thing. But it may not always involve the national press, and because election adverts are not subject to the rules of the Advertising Standards Authority, it seems little could be done to redress the following piece of nonsense and others like it, which may yet appear. I doubt IPSO would be able to do any good, though I have not investigated their rules wrt election material.

Taken from The Comet, Hitchin edition, Thursday March 26th 2015. (No link provided as subscription may be needed):

"Let's talk about climate change...

John and UKIP (United Kingdom Independence Party) do not believe in all these doom and gloom stories..."

"I am a skeptic on climate change and believe that any effects have been over exaggerated. The first half of 2014 was the coldest since records began in 1888. The Earth has warmed about 16 degrees F in the three million years following the last ice age and since 1979 the increase has been 0.19 degrees F well within the range of natural fluctuation."

John Stocker MBE UKIP Hitchin and Harpenden.

And that is it. No references of course. I will have a large poster ready in case they knock on my door, just to put them straight. Politely, of course.

Watchdog at 05:49 AM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Tristan@16..
I didn't say - the Southern Hemisphere is Cooling OR Warming..

Additionally, my point has naught to do with whether or not Antarctica's been exhibiting a Warming Climate vatiable during the past 30 years or not.

My point pertains to the fact that one should include both the Northern and Southern Hemispheric ICE Data (aka Global ICE Volumes at a given Time) IF/WHEN one is presenting -> ICE Affects upon the Globe.

As any graph of annual (or more) Arctic and Antarctic Sea Ice Extents reveal, Both hemispheres are Simultaneous experiencing Semi-Annual Cooling & Warming Phases at opposing times of the Annum.

Both hemipheres are simultaneously out of phase with one another

One Hemisphere's "Winter" occurs _during_ the other's "Summer"

At any given time, as e.g., the Southern Hemisphere Cools the Antarctic ICE Grows AND the Northern Hemisphere Warms thus the Arctic Sea Ice Shrinks..again, at any given time during any year.

The Growing Antarctic Ice Phase during the Southern Hemisphere's Semi-Annual Climate Cooling ICE Growth Phase outstrips the much smaller in Volume simultaneous occurring of Arctic Sea Ice Shrinkage.

My focus is upon the level of the _Net Cancelling Effect_ of Global Temps occurring opposionally and simultaneiously in Both Hemispheres) during any Annum.

As the shrinkage extent of Arctic's Sea Ice is indicative of the Northern Hemisphere's Warming "Summertime", the simultaneous addition of Antarctica's Ice due to the contemporaneous Cooling Winter - must be factored in - IF one is discussing impact of Global Temps upon EARTH's TOTAL ICE - and vice versa.

LASTLY, whereas you've said, "Antarctica is losing ICE Mass", NASA says that on Sept 19, 2014 (Antarctica's Winter), Antarctica reached a "New Record Maximum" level of ICE.

NASA: Antarctic Sea Ice Reaches New Record Maximum

On Sept. 19, 2014, the five-day average of Antarctic sea ice extent exceeded 20 million square kilometers for the first time since 1979, according to the National Snow and Ice Data Center. The red line shows the average maximum extent from 1979-2014. Image: NASA's Scientific Visualization Studio

http://www.nasa.gov/content/goddard/antarctic-sea-ice-reaches-new-record-maximum/

jja at 03:41 AM on 31 March 2015

Global warming and drought are turning the Golden State brown

One aspect that has not been looked at and should is the contribution of SE Asian aerosol loading as a contribution to the 'RRR'. This was implicated in the GEOmip analyses. For example: Moore et. al. (2013) http://dx.doi.org/10.1002/2013JD021060

The negative PNA-like pattern in G1-piControl is associated with a westward shift of the jet stream toward East Asia, blocking activity over the high latitudes of the North Pacific Ocean, and a strong split-flow configuration over the central North Pacific Ocean. Figure 7 displays these features with a decreased jet speed over central, west Pacific region (with across-model differences, Figure S7), and the 200 hPa geopotential height map also shows a “blocking” high pressure over the northern North Pacific under G1.

michael sweet at 01:51 AM on 31 March 2015

New measurements confirm extra heating from our carbon dioxide

Citizenschallenge,

As I understand it Jim Steele has it almost backwards. AGW causes dry places to get dryer. Heat waves are worse when there is little surface water to evaporate and cool the atmosphere. In places like California, they have had little rain. When they have a heat wave, it is much hotter than it would have been because there is no water to evaporate to cool the weather off.

AGW's twin effects of altering rainfall and making it hotter causes heat waves to be even more distructive. California has had its fourth dry rainy season. It has been record hot there for months. Expect this summer to be even hotter and have a worse fire season (another of the effects of AGW). They pray El Nino will bail them out but no luck so far on that.

KR at 01:22 AM on 31 March 2015

2015 SkS Weekly Digest #13

Or, it could just be a cartoon using artistic license :)

Tristan at 01:13 AM on 31 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog@13

A) From the glossary: The classical period for averaging climate variables is 30 years, as defined by the World Meteorological Organization.

B) Antarctica is cooling in some areas and warming rapidly in others. It's inaccurate to say the southern hemisphere is cooling. As I said, Antarctica is losing ice mass.

Manwichstick at 01:01 AM on 31 March 2015

New measurements confirm extra heating from our carbon dioxide

RE: citizenschallenge #22

Please correct me if I'm wrong: It is my understanding that heat waves (high pressure domes) are a consequence of wind patterns (or lack there of), primarily. So both the start of a heat wave, and its ultimate conclusion, are at the hands of a much larger-scale planetary wind/ocean currents.

The idea that "local" humidity effects the duration/severity of heat waves seems a bit like a "forest for the trees" type of error - to me. It makes sense that local humidity is important - but not really THAT important.

If any one can clarify...

DSL at 00:02 AM on 31 March 2015

2015 SkS Weekly News Roundup #13A

Kaz, at the risk of "dogpiling," I'll provide another piece.

Climate is in a constant state of change and has been over the course of Earth's history. Yet for most of that history, climate has changed slowly--slowly enough that species have been able to migrate/adapt, for the most part. It's only when climate changes rapidly or to an extreme condition (deep cold or deep warmth) that many species have problems.

The current warming is extremely rapid. The Paleocene-Eocene Thermal Maximum, about 55 million years ago, was one of the most rapid sustained warmings in Earth's history. Right now, we're doing about 10x to 40x the rate of PETM warming, depending on the method one chooses to compare.

This might be no big deal if we knew that the warming was going to reverse course soon. However, there is no physical reason why that would happen, and every physical reason why it should continue for several centuries--or longer if we continue to dig up fossil carbon and dump it into the atmosphere.

CO2 is essential to keeping the planet warm enough for a robust array of life. It always has been. Yet that same process--the "greenhouse effect"--can be enhanced, and that's what we're doing. Nature hasn't increased atmospheric CO2 this rapidly in at least 300 million years. We are doing it by taking fossil carbon that was stored over tens of millions of years and dumping it into the atmosphere in a matter of a few centuries.

One Planet Only Forever at 23:48 PM on 30 March 2015

2015 SkS Weekly Digest #13

The ice could also be air free with enough of the top cube out of the water that it is holding down the rest of the cubes. This can occur in a tumbler where the cubes are kept from shifting sideways to rise to the surface.

However, given the number of cubes shown below the surface in the image almost the entire top cube would have to be out of the water, unless the water was very warm.

Composer99 at 23:41 PM on 30 March 2015

New measurements confirm extra heating from our carbon dioxide

citizenschallenge:

I don't have a cite, but to the best of my knowledge:

(1) A heat wave does not require the absence of atmospheric water vapour, or indeed of water stored in soil, etc.. IMO your interlocutor needs to provide a cite to support the claim "heat waves usually occur under very dry conditions". (Obviously not a veteran of Ottawa, Ontario heat waves, then.)

(2) Atmospheric water vapour is geographically and temporally highly variable (e.g. there is less of it in, say, desert regions, or in polar regions during the winter, than, say the wet tropics).

I can't say I know much about heat wave formation, but I'm rather doubting the person you are quoting does, either.

juggared at 23:25 PM on 30 March 2015

CO2 only causes 35% of global warming

There were many ways temperature or other climate features could influence the carbon dioxide level one way or another. Perhaps variations of temperature and of weather patterns caused land vegetation to release extra CO2, or take it up... perhaps the oceans were involved through massive changes in their circulation or ice cover... or through changes in their CO2-absorbing plankton, which would bloom or decline insofar as they were fertilized by minerals, which reached them from dusty winds, rivers, and ocean upwelling, all of which could change with the climate... or perhaps there were still more complicated and obscure effects. Into the 21st century, scientists kept finding new ways that warming would push more of the gas into the atmosphere. As one of them remarked, "it is difficult to explain the demise of the ice sheets without the added heating from CO2 ... this gas has killed ice sheets in the past and may do so again.

Watchdog at 23:09 PM on 30 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Philippe@10
Yes, that 10yr graph only establishes a "stability" over 10 yrs as it indicates that 2014 was not a particularly 'Warm' year in that time.

In your opinion, what time period is long enough to establish whether or not tGlobal Climate is undergoing a Cooling vs Warming Phase? 10yrs? 150yrs? 2000yrs? 20,000yrs? 400,000yrs?

Tristan@11 - At the same time As the Northern Hemisphere Warms,
the So. Hemisphere - including the Far Larger ICY Antarctica - Cools..
Total Global Heat content is a continuous Global Measurement.

CBDunkerson at 22:56 PM on 30 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Watchdog, you look at an ice area graph showing 2012 minimum extent (not area) nearly half the size of 2005 minimum extent and conclude that this indicates it has been "relatively stable"?

We have very different definitions of 'stable'.

CBDunkerson at 22:49 PM on 30 March 2015

Ipso proves impotent at curbing the Mail's climate misinformation

ryland, why would IPSO do anything about the 'failure' to point out an irrelevancy?

'That is steam, not smoke!'

Um, ok... so what? How is that relevant to global warming? People might over-estimate the amount of smoke emitted by power plants (since steam output is greater)? And that would oversell global warming how exactly? Smoke is particulate matter... which causes cooling.

Watchdog at 22:46 PM on 30 March 2015

Scientists link Arctic warming to intense summer heatwaves in the northern hemisphere

Daniel Bailey at 21:43 PM on 30 March 2015

2015 SkS Weekly News Roundup #13A

"The Earth has gone through cooling and warming more times than Kim Kardashian has waved her backside about"

Saying that since climate change existed before mankind is proof that this iteration of change is not caused by man is like saying that the darkness of night disproves the existence of the sun.

It's not true and it just makes you sound uninformed.

If you wish to pursue your position further, read this post and the comments underneath it and then (and only then) place any remaining concerns on the the comment thread there:

Climate Change Cluedo: Anthropogenic CO2

Glenn Tamblyn at 20:50 PM on 30 March 2015

2015 SkS Weekly News Roundup #13A

Kaz

For most of the Earth's history the only life on Earth was bacteria. Anything we might recognise as plants or animals only appeared in the last 500-600 million years. Whereas bacteria (and their even older cousins, Archaea) go back at least 3 billion years and maybe as far back as 3.8 billion years. We complex organisms - people, poplars, prawns etc are recent interlopers.

And those ancient bacteria transformed the planet and the atmosphere more than 2 billion years before anything 'complex' appeared.

Google 'The Great Oxygenation Event' as an example.

Stephan at 18:22 PM on 30 March 2015

Climate's changed before

Re. [3], [5]: Hoyt's argument is flawed on a very basic level. It goes like this: "Water vapour has a atmospheric life time of about a week. So if there is more water vapor in the atmosphere, we must somehow lift that water from the ground up into the atmosphere every week. That requires energy, which must come from somewhere. There is not enough energy to do that. So water vapor cannot increase as much as claimed". What he ignores is the very simple fact that that energy required to lift the water is not lost to the system. Whenever water vapor leaves the atmosphere (via precipitation), those raindrops and snow flakes and hailstones fall back to the ground, and their potential energy is converted back to kinetic energy, and ultimately heat.

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