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Climate Links: Resilient Arctic & Pacific Decadal Oscillation

Items that caught my eye this morning on Twitter:

Scientists: Arctic Is More Resilient To Global Warming Than We Thought” Who is “We” and why did “we” think the Arctic wasn’t resilient?  The second is easier to answer: because climate scientists with bullhorns told us for years that the Arctic was “DOOMED!”  I’ve written about this topic and knew when the record low extent and volume occurred in 2012 that it was likely one bad year and not the end of the world.  I haven’t seen or heard from those same scientists who breathlessly told the public about the doomed Arctic in 2012 that they were wrong (boy, were they wrong!).  While this article makes that point today (3 years too late), I don’t expect anyone to remember it when the Arctic has another bad summer.  2013 was a good Arctic summer: cooler than recent years – and guess what? Arctic ice responded by … growing – you know, what it’s supposed to do according to physics.  Headslap.

To truly grasp what we’re doing to the planet, you need to understand this gigantic measurement”  This is an article about “giga”: what the prefix means and how people should know about it.  I disagree with it from the perspective that the explanations don’t utilize anything truly useful.  For example: a gigaton is “more than 6 million blue whales”.  Who knows how much a big whale weighs?  Can you envision 6 million of them?  The basic problem with giga is it is so big that it defies our everyday experiences.  The superficial problem is despite being written by someone who understands science, the article likely misses its intended audience and thus is not useful.

At the risk of delving too far into technical issues, this article is useful for me personally based on relevance to my geographic region’s upcoming winter weather: “Subtle Differences to Previous El Niños Key to Winter Forecast, And Why the PDO Matters“.  The PDO is the Pacific Decadal Oscillation – a low-frequency natural climate pattern that has direct and indirect influences on weather across at least the western half of the nation.  Many people in my professional community are aware that there is currently a strong El Nino in the equatorial Pacific.  I noted from recent write-ups that there are also warm sea surface temperature anomalies in the north Pacific (e.g., off the west coast of the U.S.) – in addition to the warm anomalies across the central and eastern equatorial Pacific (hallmarks of El Ninos).

The northern Pacific anomalies are an oddity and this article helps explain why they might be present.  In the late 1990s, the PDO likely entered into a cool pattern, which helps explain a couple of things.  First, El Ninos during the 2000s and 2010s had lower amplitude (cooler).  And second, global temperatures didn’t rise as quickly since 1998 as they did during the previous PDO phase (1977-1998).  This observation is also known as the global warming “hiatus” or “pause”.  A cool PDO means Pacific sea surface temperatures are cooler than average.  One effect of this is the Pacific absorbs heat from the atmosphere and keeps the atmosphere cooler than it otherwise would be.  The opposite is also true: warmer than average Pacific SSTs releases more heat to the atmosphere than is absorbed and the atmosphere warms more than average.

Which leads me to the next article: “Has the PDO Flipped to a Warming Phase?”  The PDO typically stays in a warm or cool regime for 10 to 30 years – hence the “multidecadal” characterization.  As I wrote above, the PDO moved into a cool phase in the late 1990s.  Recent positive temperature anomalies (since 2014) might indicate that the PDO is temporarily positive or it might indicate the PDO switched back to a positive or warm phase.  This has significant implications for global weather patterns until it switches back to its negative phase.  For example, I wrote above that there is currently a strong El Nino.  If the PDO switched to a positive phase, it could enhance any El Nino.  It would also do what I described above: release heat back into the atmosphere.  This means the global warming “hiatus” is, if the PDO switches, over.

Back to the Colorado forecast.  With a warmer north and equatorial Pacific (positive PDO and ENSO), what kind of winter can we expect?  The answer won’t surprise you: it’s hard to tell.  There are few similar historical examples that scientists can use to issue a reliable forecast.  They have to determine if warmer ocean temperatures persist and how the atmosphere’s jet stream responds.  Ridge and trough locations over the western US will ultimately determine when we get snow and how much snow we get during each storm.


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“Arctic Sea Ice More Resilient Than Previously Thought”

Welcome back to me.  I took a break due to heavy class load and studying for qualifying exams.  I’m looking forward to a good 2015.  I tagged plenty of material while I was short on writing time, so stay tuned for lots of climate and energy science and policy discussions.

File this in the “who’da thunk?” category: research presented at the 2014 American Geophysical Union’s annual meeting showed recent summers over the Arctic were cooler than normal and as a result, Arctic sea ice melt wasn’t as extensive as previous record low years.

I remember all too many climate scientists tripping over one another in their mad rush to a microphone to declare that the Arctic would be ice-free in just a few short years – a claim I thought was silly and dangerous.

Why silly?  Because these same scientists, preaching objectivism and claiming science has an impenetrable hold on truth over all other comers, no more understood the cryosphere then than they do now.  This most result lays bare that type of truth: we don’t know enough about the cryosphere system to accurately or precisely project conditions in the near to medium future.  While it is very likely that summer Arctic sea ice will be missing at some point in the future, the timing of that event is very much in question.  I think it will be sooner than the IPCC AR4 model projections (see quoted statement below), which read: “In some projections, arctic late-summer sea ice disappears almost entirely by the latter part of the 21st century.”  Papers written prior to the 2014 AR5 report projected ice-free conditions between 2037 and 2050.  But there is still 35 years in the meantime.  What will Arctic sea ice be like during those 35 years?  Like good scientists, we should collect data as well as run and test models during that time to more fully understand the system.  But good scientists do not claim knowledge they do not have.

The 2007 IPCC report made clear the level of uncertainty that exists:

A systematic analysis of future projections for the Arctic Ocean circulation is still lacking. Coarse resolution in global models prevents the proper representation of local processes that are of global importance (such as the convection in the Greenland Sea that affects the deep waters in the Arctic Ocean and the intermediate waters that form overflow waters).

Which leads to the dangerous part of scientists’ misguided efforts to “educate” the public at every turn, a strategy motivated by perceived successes by fossil fuel corporations and their backers.  Moreover, the perceived extreme position of those corporations elicited a corresponding response from scientist-activists.  One problem with this is the potential to appear foolish to the very people scientists are trying to convince of real climate risks when dire projections end up wrong.  Scientists historically and currently enjoy wide-spread and deep respect by the public.  I can’t believe that will continue if, for instance, grandiose claims of significant events end up wrong.  How often do you and your friends make fun of the local weatherman after a busted forecast?  I think scientists should instead tap into that deep reservoir of trust and leverage it intelligently.  If the best science indicates an ice-free Arctic by 2035-2050, then say that.  If conditions change radically, there will of course be a ready explanation that the public will gladly receive.


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55.7% of the Contiguous United States in Moderate or Worse Drought – 12 Feb 2013

According to the Drought Monitor, drought conditions are relatively unchanged in the past two weeks. As of Feb. 12, 2013, 55.7% of the contiguous US is experiencing moderate or worse drought (D1-D4). The percentage area experiencing extreme to exceptional drought increased from 19.4% to 17.7% in the last two weeks. Percentage areas experiencing drought across the West stayed mostly the same while snowpack increased. Drought across the Southwest decreased slightly. Meanwhile, storms improved drought conditions in the Southeast.

This post precedes a significant snow event across the High and Great Plains.  The NWS expects up to a foot of snow in some areas of the Plains over the next couple of days, which will provide about 1″ of liquid water equivalent.  Since these areas currently suffer from a 2-4″ liquid water deficit, this storm will not break the short-term drought.  Moreover, long-term drought will only be broken by substantial spring and summer rainfall.  After one or two more Drought Monitor updates, we should see some welcome differences in these maps.

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Figure 1 – US Drought Monitor map of drought conditions as of the 12th of February.

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Figure 2 – US Drought Monitor map of drought conditions in Western US as of the 12th of February.  Some small relief is evident in the past week, including some changes in the mountains as storms recently dumped snow across the region.  Mountainous areas and river basins will have to wait until spring for snowmelt to significantly alleviate drought conditions.

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Figure 3 – US Drought Monitor map of drought conditions in Colorado as of the 12th of February.  Drought conditions held mostly steady across the state in the past week.  For the first time in over a month, less than 100% of CO is experiencing Severe drought conditions.  This improvement occurred over the southwestern portion of the state due to mid-season snow storms.  Unfortunately, Exceptional drought conditions expanded over the northeastern plains.

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Figure 4 – US Drought Monitor map of drought conditions in Southeast US as of the 12th of February.  As mentioned above, drought conditions contracted a little and grew less severe in the past couple of weeks.  The worst hit area, in central Georgia, has experienced the longest duration drought conditions on this map.

Cooler than normal sea-surface temperatures (SSTs) are present in the eastern Pacific, according to current MJO and ENSO data.  Additionally, eastern Pacific SSTs are cooler than the climatic average due to the current negative phase of the IPO.  This in turn is due in part to global warming, which is causing warmer western Pacific and Indian Ocean SSTs than usual.  The cool SSTs in the eastern Pacific initiate and reinforce air circulations that generally keep precipitation away from the Southwest and Midwest US.  This doesn’t mean that drought will be ever-present; only that we are potentially forcing the climate system toward more frequent drought conditions in these regions.  Some years will still be wet or normal; other years (increasing in number) will be dry.  This counters skeptics who claim that more CO2 and warmer temperatures are better for plants.  If there is no precipitation, plants cannot take advantage of longer growing seasons.  Moreover, we will experience years with increased food pressure.  These conditions’ extent in the future is up to us and our climate policy (or lack thereof).

While MJO, ENSO, and IPO are all in phases that tend to deflect storm systems from the Southwest, this week’s storm demonstrates that the conditions are not ever-present.  Weather variability still occurs with the dryer regime.  Put another way, weather is not climate.


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57.7% of Contiguous US in Moderate or Worse Drought – 29 Jan 2013

According to the Drought Monitor, drought conditions are relatively unchanged in the past two weeks. As of Jan. 29, 2013, 57.7% of the contiguous US is experiencing moderate or worse drought (D0-D4). The percentage area experiencing extreme to exceptional drought increased from 19.3% to 19.4%. Percentage areas experiencing drought across the West stayed mostly the same at the end of January as they were at in the middle. Drought across the Southwest decreased slightly. Meanwhile, drought across the Southeast grew due to relative lack of precipitation.

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Figure 1 – US Drought Monitor map of drought conditions as of the 29th of January.

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Figure 2 – US Drought Monitor map of drought conditions in Western US as of the 29th of January.  Some small relief is evident in the past week, but note the lack of change of drought conditions across the regions, despite recent snows throughout the mountains.  Mountainous areas and river basins will have to wait until spring for snowmelt to help start to alleviate drought conditions.

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Figure 3 – US Drought Monitor map of drought conditions in Colorado as of the 29th of January.  Drought conditions held steady across the state in the past week.  100% of Colorado experienced Severe or worse drought conditions for the past three weeks.

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Figure 4 – US Drought Monitor map of drought conditions in Southeast US as of the 29th of January.  As mentioned above, drought conditions expanded and worsened in the past couple of weeks.  The worst hit area, in central Georgia, has experienced the longest duration drought conditions on this map.  Drought has expanded and contracted around this area during that time.

The latest seasonal (three-month) outlook from the National Weather Service predicts enhanced chances for above-average temperature and below-average precipitation for the central US.  This means that drought conditions are likely to continue for at least another three months and probably longer if prevailing conditions do not change.  One of the major weather stories of 2012 was drought; 2013 is shaping up to have the same story.

What is causing this?  A combination of factors: the Arctic Oscillation (AO), the Madden-Julian Oscillation (MJO), the El-Nino and Southern Oscillation (ENSO), the Interdecadal Pacific Oscillation (IPO), and background climate warming.

As I discussed in my last drought post:

The lack of sea ice in the Arctic back in September is part of what caused the negative phase of the AO.  The Arctic Ocean absorbed solar radiation instead of reflecting it back to space.  The ocean then slowly released that heat to the atmosphere before new ice could form.  That extra heat in the atmosphere changed how and where the polar jet stream established this winter.  Instead of a tight loop near the Arctic Circle, the jet stream has grown in North-South amplitude, allowing cold air to pour to latitudes more southerly than usual and warm air to move over northern latitudes.  The large amplitude jet has kept the normal type of storms from moving over locations that used to see them regularly during the winter.

An active MJO is keeping trade winds stronger than they otherwise would be, which piles up warm ocean water in the western tropical Pacific Ocean.  This causes cool, deep ocean water to rise in the eastern Pacific, as seen in Figure 5.

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Figure 5Madden-Julian Oscillation conditions as of 2 Feb 2013 from NOAA-CPC.

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Figure 6ENSO conditions as of 2 Feb 2013 from NOAA-CPC.

Cooler than normal sea-surface temperatures (SSTs) are present in the eastern Pacific due to the current MJO and ENSO data.  Additionally, eastern Pacific SSTs are cooler than the climatic average due to the current negative phase of the IPO.  This in turn is due in part to global warming, which is causing western Pacific and Indian Ocean SSTs warmer than usual.  The cool SSTs in the eastern Pacific initiate and reinforce air circulations that generally keep precipitation away from the Southwest and Midwest US.  This doesn’t mean that drought will be ever-present; only that we are potentially forcing the climate system toward more frequent drought conditions in these regions.  Some years will still be wet or normal; other years (increasing in number) will be dry.  This is a counter to skeptics who claim that more CO2 and warmer temperatures are necessarily better for plants.  If there is no precipitation, plants cannot take advantage of longer growing seasons.  Moreover, we will experience years with food pressure.  These conditions’ extent in the future is up to us and our climate policy (or lack thereof).


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58.9% of Contiguous US in Moderate or Worse Drought – 15 Jan 2013

The storm systems that moved over the US in the past month alleviated some of the drought conditions across the US, according to the Drought Monitor. As of Jan 15, 2013, 58.9% of the contiguous US is experiencing moderate or worse drought (D0-D4). The percentage area experiencing extreme to exceptional drought decreased from 21.3% to 19.4%. Percentage areas experiencing drought across the West stayed mostly the same in the middle of January as they were at the end of December. Drought across the High Plains expanded slightly during the same period. Meanwhile, drought across the Southeast and Midwest shrank due to the aforementioned storm systems.

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Figure 1 – US Drought Monitor map of drought conditions as of the 15th of January.

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Figure 2 – US Drought Monitor map of drought conditions in Western US as of the 15th of January.  Note the lack of change of drought conditions across the regions, despite recent snows throughout the mountains.  Mountainous areas and river basins will have to wait until spring for snowmelt to help start to alleviate drought conditions.

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Figure 3 – US Drought Monitor map of drought conditions in Midwest US as of the 15th of January.  This region also has not seen any meaningful shift in drought conditions recently.  The Plains will likely have to wait until spring and summer for drought relief.  This sector of the country does plant a significant amount of crops.  The winter wheat crop has already been devastated.

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Figure 4 – US Drought Monitor map of drought conditions in Colorado as of the 15th of January.  Drought conditions worsened slightly across the state in the past week.  Now, 100% of Colorado is experiencing Severe or worse drought conditions.  The percentage area with Extreme drought conditions is 5% higher than last week.  There was no significant difference in Exceptional drought area since last week.

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Figure 5 – US Drought Monitor map of drought conditions in Colorado as of July 31, 2012.  This figure shows how extensive the current drought is – both in space and time.  Severe or worse drought has afflicted close to 100% of the state for almost six months now.  While specific regions of the state have received some rain or snow, it hasn’t been enough to break the drought yet.  The percent area with Extreme or worse drought has decreased from 73.67% on July 24th to 65.35% on July 31st to 58.64% on January 15th.  The southeast part of the state has seen the worst of conditions, as Figure 5 and 6 demonstrate.

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Figure 6 – US Drought Monitor map of drought conditions in Colorado as of June 14, 2011.  Eighteen months ago, more than half of Colorado was drought-free.  As you can see, the southeast part of the state has seen Severe or worse drought conditions for a long time now.

The US is not likely to see drought relief through March (drought predictions are accurate for ~3 months at a time) .  A negative Arctic Oscillation (AO; Figure 7) is challenging the return to ENSO-neutral conditions, which should allow normal precipitation to fall over the US.  The AO has been negative in previous winters and it has caused the severe winter storms that affected the northeastern US as well as UK (record wet year in 2012) and Scandinavia.

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Figure 7Arctic Oscillation time series from NOAA’s Climate Prediction Center.

The lack of sea ice in the Arctic back in September is part caused the negative phase of the AO.  The Arctic Ocean absorbed solar radiation instead of reflecting it back to space.  The ocean then slowly released that heat to the atmosphere before new ice could form.  That extra heat in the atmosphere changed how and where the polar jet stream established this winter.  Instead of a tight loop near the Arctic Circle, the jet stream has grown in N/S amplitude, allowing cold air to pour to latitudes more southerly than usual and warm air to move over northern latitudes.  The large amplitude jet has kept the normal type of storms from moving over locations that used to see them regularly during the winter.

Hence, the drought we see now over the US is causally linked to the Arctic Oscillation as well as the long-lasting, moderate La Niña (2010-2012).  Both of the natural variations exist on top of the background climate, which we are warming (this is why there was record low Arctic sea ice in 2012).  We will continue to see the climate modulate normal weather conditions until we stop emitting greenhouse gases.  As I’ve written, that isn’t likely to happen any decade soon.


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How the IPCC Underestimated Climate Change – Scientific American article

Scientific American published an article summarizing what I’ve written about for a couple of years: the IPCC’s projections aren’t 100% correct.  Gasp – the horror!  But, contrary to what skeptics think, the direction the IPCC’s reports were wrong are opposite of what they claim.  The projections time and again underestimated future changes.  I think a valid complaint, and one I’ve made many times myself, is that the IPCC process is too conservative – it takes too long to get the kind of consensus they’re looking for.  Rapidly changing conditions are not well handled by the IPCC process.  When there is conflicting evidence of something, the IPCC has tended to say nothing in an effort not to upset anybody.  The good news is there are indications this is changing.  The list:

1. Emissions

This is the biggest one.  Too many studies focused on moderate emission pathways, when yearly updates showed our actual emissions were on the high range of those considered by the IPCC.  I actually posted on this two days ago: CO2 Emissions Continue to Track At Top of IPCC Range.  This has implications for every other process that follows.

2. Temperature

More accurately, energy in the climate system is the variable of interest.  It is easy to point out that temperatures since 2000 haven’t increased as much as projected.  It is also easy to compare observed trends since 1980 and claim AR4 models over-predicted temperature rise.  This conflates a couple of issues: the AR4 wasn’t used to project since 1980.  More importantly, the difference between observed trends since 1980 and projected temperatures from half of the AR4 models was less than 0.04°C (0.072°F).  That’s pretty darned small.  With respect to the trend since 2000, the real issue is energy gain.  The vast majority of energy has accumulated in the oceans:

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More specifically, if the heat is transported quickly to the deep ocean (>2000ft), the sea surface temperature doesn’t increase rapidly.  Nor does atmosphere or land temperatures change.  This is true at least in the short-term.  When the ocean transports this heat from the deep back to the surface, we should be able to more easily measure that heat.  Put simply, the temporary hiatus of temperature rise is just that: temporary.  Are we prepared for when that hiatus ends?

The relatively small increase in near-surface air and land temperatures is thus explained.  The IPCC never claimed the 4.3° to 11.5°F temperature rise (AR4 projection) would happen by 2020 – it is likely to happen by 2100.  Expect more synergy between projected temperatures and observed temperatures in the coming years.  Also remember that climate is made up of long-term weather observations.

Additionally, aerosols emitted by developing nations have been observed to reflect some of the incoming solar radiation back to space.  Once these aerosols precipitate out of the atmosphere or are not emitted at some point in the future, the absorption of longwave radiation by the remaining greenhouse gases will be more prominent.  The higher the concentration of gases, the more radiation will be absorbed and the faster the future temperature rise is likely to be.  These aerosols are thus masking the signal that would otherwise be measured if they weren’t present.

3. Arctic Meltdown

This is the big story of 2012.  The Arctic sea ice melted in summer 2012 to a new record low: an area the size of the United States melted this year!  Even as late as 2007 (prior to the previous record-low melt), the IPCC projected that Arctic ice wouldn’t decrease much until at least 2050.  Instead, we’re decades ahead of this projection – despite only a relatively small global temperature increase in the past 25 years (0.15°C or so).  What will happen when temperatures increase by multiple degrees Centigrade?

4. Ice sheets

These are the land-based sheets, which are melting up to 100 years faster than the IPCC’s first three reports.  2007’s report was the first to identify more rapid ice sheet melt.  The problem is complex cryospheric dynamics.  Understandably, the most remote and inhospitable regions on Earth are the least studied.  Duh.  That’s changing, with efforts like the fourth International Polar Year, the results of which are still being studied and published.  Needless to say, modern instrumentation and larger field campaigns have resulted in advances in polar knowledge.

5. Sea Level Rise

It’s nice being relevant.  I just posted something new on this yesterday: NOAA Sea-Level Rise Report Issued – Dec 2012.  The 3.3mm of sea-level rise per year is higher than the 2001 report’s projection of 2mm per year.  Integrated over 100 years, that 1mm difference results in 4″ more SLR.  But again, with emission and energy underestimates, the 3.3mm rate of SLR is expected to increase in future decades, according to the latest research.  Again, another mm per year results in another 4″ 100 years from now.  Factors affecting SLR that the IPCC didn’t address in 2007 includes global ocean warming (warmer water takes up more volume), faster ice sheet melt, and faster glacial melt.  Additionally, feedback mechanisms are still poorly understood and therefore not well represented in today’s state-of-the-art models.

6. Ocean Acidification

The first 3 IPCC reports didn’t even mention this effect.  In the past 250 years, ocean acidity has increased by 30% – not a trivial amount!  As the article points out, research on this didn’t even start until after 2000.

7. Thawing Tundra

Another area that is not well-studied and therefore not well understood.  The mechanics and processes need to be observed so they can be modeled more effectively.  1.5 trillion tons of carbon are locked away in the currently frozen tundra.  If these regions thaw, as is likely since the Arctic has observed the most warming to date, methane could be released to the atmosphere.  Since methane acts as a more efficient GHG over short time frames, this could accelerate short-term warming much more quickly than projected (See temperatures above).  The SciAm article points out the AR5, to be released next year, will once again not include projections on this topic.

8. Tipping Points

This is probably the most controversial aspect of this list.  Put simply, no one knows where potential tipping points exist, if they do at all.  The only way we’re likely to find out about tipping points is by looking in the past some day in the future.  By then, of course, moving back to other side of the tipping point will be all but impossible on any time-frame relevant to people alive then.

Summary

There are plenty of problems with the UNFCCC’s IPCC process.  Underestimation of critical variables is but one problem plaguing it.  Blame it on scientists who, by training, are very conservative in their projections and language.  They also didn’t think policymakers would fail to curtail greenhouse gas emissions.  Do policymakers relying on the IPCC projections know of and/or understand this nuance?  If not, how robust will their decisions be?  The IPCC process needs to be more transparent, including allowing more viewpoints to be expressed, say in an Appendix compendium.  The risks associated with underestimating future change are higher than the opposite.


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Short Arctic Sea Ice Update – 20120723

Here, in a sneak peak of my monthly `State of the Poles` post, I wanted to mark a significant event: the area of Arctic sea ice has fallen below the climatological minimum.  This occurs with ~6 weeks left in the Arctic melt season.  In similar fashion as in other recent years, UIUC data show Arctic sea ice area values at a stunning -2 million sq. km. below the average value for this date in time.  Instead of 6.5 million sq. km., today’s value is 4.5 million sq. km., the record lowest for this calendar day.  Conditions on the Pacific side of the Arctic sea ice pack (another graphic here) are starting to deteriorate, so rapid melt of additional hundreds of thousands of sq. km. of sea ice could occur in the next month or so.  The recorded history yearly minimum sea ice area is ~2.91 million sq. km.  Stay tuned for this year’s minimum, which will likely occur in early September.

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