Sunday, November 20, 2016

Sea ice is shrinking


Arctic sea ice extent fell 0.16 million km² from November 16 to November 19, 2016, as illustrated by above ads.nipr.ac.jp/vishop image. The image below, based on NSIDC data, shows the Arctic sea ice shrinking 49,000 km² in four days.


This is happening at a time when there is little or no sunlight reaching the Arctic, as illustrated by the image below.


The image below was created by Torstein Viddal and earlier posted at the Arctic Sea Ice Collapse blog.



This recent fall in extent is partly due to strong winds, as illustrated by the image on the right.

Mostly, though, the lack of sea ice over the Arctic Ocean is caused by very warm water that is now arriving in the Arctic Ocean.

During the northern summer, water off the coast of North America warms up and gets pushed by the Coriolis force toward the Arctic Ocean. It takes several months for the water to travel along the Gulf Stream through the North Atlantic.

It has taken until now for the Arctic Ocean to bear the brunt of this heat.

As the image below shows, record sea surface anomalies showed up near Svalbard on October 31, 2016, when this heat first arrived in the Arctic.


On October 31, 2016, the Arctic Ocean was as warm as 17°C or 62.7°F (green circle near Svalbard), or 13.9°C or 25°F warmer than 1981-2011. This indicates how much warmer the water is beneath the surface, as it arrives in the Arctic Ocean from the Atlantic Ocean.

Moreover, Antarctic sea ice is also falling, reflecting the warming of oceans globally. For some time now, Antarctic sea ice extent has been at a record low for the time of the year.  On November 19, 2016, the combined extent of Arctic and Antarctic sea ice was 22.423 million km², as the image below shows.


This constitutes a fall in global sea ice extent of 1.085 million km² (418,900 square miles) since November 12, 2016, when global sea ice extent was 23.508 million km².

Let's look at those figures again. On Saturday November 12, 2016, global sea ice extent was 23.508 million km². On Saturday November 19, 2016, global sea ice extent was 22.423 million km². That's a fall of more than one million km² in one week.

By comparison, that's more than the combined size of ten European nations (such as Switzerland, Austria, Hungary, Germany, Denmark, the Netherlands, Belgium, Luxembourg, the United Kingdom and Ireland).

Or, it's more than the combined size of seventeen States of the United States (such as Ohio, Virginia, Tennessee, Kentucky, Indiana, Maine, South Carolina, West Virginia, Maryland, Hawaii, Massachusetts, Vermont, New Hampshire, New Jersey, Connecticut, Delaware and Rhode Island).

How much additional energy does Earth retain, due to such an albedo change? If it was a total albedo flip, it would be some 0.68 W/m². A conservative estimate would be a 50% albedo flip, as the image below illustrates, so this would mean that Earth now retains some 0.34 W/m² extra energy.

Thick sea ice covered with snow can reflect as much as 90% of the incoming solar radiation. After the snow begins to melt, and because shallow melt ponds have an albedo (or reflectivity) of approximately 0.2 to 0.4, the surface albedo drops to about 0.75. As melt ponds grow and deepen, the surface albedo can drop to 0.15, while the ocean reflects only 6% of the incoming solar radiation and absorbs the rest.



So, this one-week fall in sea ice extent means there now is an additional warming of some 0.34 W/m². By comparison, the warming impact relative to the year 1750 of all carbon dioxide emitted by people was 1.68 W/m² in the most recent IPCC assessment report (AR5).

There's more! As sea ice declines, there is not only albedo loss due to a fall in extent, but there is also albedo loss over the remaining sea ice, which turns darker as it melts.

The image below shows the fall in extent of Antarctic sea ice up to November 20, 2016. On November 20, 2016, Antarctic sea ice extent was 2.523 million km² less than its extent was at the same time of the year in 2015.


How much more energy is now retained by Earth than in 2015? Assuming a 50% albedo flip for this extent loss and a similar albedo loss that's taking place over the remaining ice, this means that Earth is now retaining an extra amount of energy (compared to 2015) that is equal to all the warming relative to pre-industrial due to carbon dioxide emitted by people.

Above image shows how the difference between 2016 and 2015 Antarctic sea ice extent grew between November 4 and November 23. On November 23, 2016, Antarctic sea ice extent was 2.615 million km² smaller than on November 23, 2015.

That means that a huge amount of sunlight is now absorbed by the ocean, rather than reflected back into space.

The animation on the right (added later) shows the decline of the sea ice around Antarctica over the period from November 16, 2016, to January 4, 2017. For comparison, the blue line shows the 1979-2000 average.

The situation is dire and calls for comprehensive and effective action as described in the Climate Plan.



Sunday, November 13, 2016

Monthly CO₂ not under 400 ppm in 2016

For the third year in a row, global carbon dioxide emissions from fossil fuels and industry (including cement production) have barely grown, as the Global Carbon Project image below shows:


Nonetheless, CO₂ levels have continued to rise and, as illustrated by the trend on the image below, they may even be accelerating.


According to NOAA, annual mean global carbon dioxide grew from 2004-2014 by an average 2.02 ppm per year. For 2015 the growth rate was 2.98 ppm. As an indication for what the 2016 growth rate will be, global CO₂ levels grew by 3.57 ppm between September 2015 and September 2016, and by 3.71 ppm between October 2015 and October 2016. How could growth in CO₂ levels in the atmosphere possibly be accelerating, given that emissions from fossil fuel burning and cement production have barely risen over the past few years?

Deforestation and other land-use changes, in particular wildfires

During the decade from 2006 to 2015, emissions from deforestation and other land-use change added another 1.0±0.5 GtC (3.3±1.8 GtCO₂) on average, on top of the above emissions from fossil fuel and cement. In 2015, according to the Global Carbon Project, deforestation and other changes in land use added another 1.3 GtC (or 4.8 billion tonnes of CO₂), on top of the 36.3 billion tonnes of CO₂ emitted from fossil fuels and industry. This rise in emissions from deforestation and other changes in land use constitutes a significant increase (by 42%) over the average emissions of the previous decade, and this jump was largely caused by an increase in wildfires over the past few years.

In 2016, monthly mean global CO₂ levels didn't get below 400 ppm. It was the first time that this happened in over 800,000 years.


On their way up, global CO₂ levels fluctuate with the seasons, typically reaching an annual minimum in August. In August 2016, CO₂ levels reached a low of 400.44 ppm, i.e. well above 400 ppm. In September 2016, carbon dioxide levels had gone up again, to 400.72 ppm. Importantly, a trend is contained in the data indicating that growth is accelerating and pointing at a CO₂ level of 445 ppm by the year 2030.

Sensitivity

Meanwhile, research including a 2014 study by Franks et al. concludes that IPCC was too low in its estimates for the upcoming temperature rise locked in for current CO₂ levels. A study by Friedrich et al. updates IPCC estimates for sensitivity to CO₂ rise, concluding that temperatures could rise by as much as 7.36°C by 2100 as a result of rising CO₂ levels.

When also taking other elements than CO₂ more fully into account, the situation looks to be even worse than this, i.e. the global temperature rise could be more than 10°C (or 18°F) over the coming decade, as further described at the extinction page.

Land sink


Above image also shows an increase of the land sink over the years, which a recent study attributes to higher CO₂ levels in the atmosphere. While this increase of the land sink appears to have held back a stronger temperature rise for some time, there are indications that this land sink is now decreasing. A recent study suggests that some 30 ± 30PgC could be lost from the top 10 cm surface soil for a 1°C, and some 55 ± 50 PgC for a 2°C rise of global average soil surface temperatures, which would increase CO₂ levels in the atmosphere by some 25 ppm. The study adds that, since high-latitude regions have the largest standing soil C stocks and the fastest expected rates of warming, the overwhelming majority of warming-induced soil C losses are likely to occur in Arctic and subarctic regions. See also the video below for more on this study.

In other words, land is now taking up less carbon and is contributing more and more to global warming:
  • Deforestation and Soil Degradation: Agricultural practices such as depleting groundwater and aquifers, plowing, mono-cultures and cutting and burning of trees to raise livestock can significantly reduce the carbon content of soils, along with soil moisture and nutrients levels.
  • Climate change and extreme weather events: The recent jump in global temperature appears to have severely damaged soils and vegetation. Soil carbon loss and enhanced decomposition of vegetation appear to have occurred both because of the temperature rise and the resulting extreme weather events such as heatwaves, drought, dust-storms and wildfires, and storms, hail, lightning, flooding and the associated erosion, turning parts of what was once a huge land sink into sources of CO₂ emissions. Even worse, such extreme weather events can also lead to emissions other than CO₂ emissions, such as of soot, nitrous oxide, methane and carbon monoxide, which can in turn cause raise levels of ground-level ozone, thus further weakening vegetation and making plants even more vulnerable to pests and infestations.
  • Albedo: As a 2009 study warned, higher temperatures could also cause decreased canopy transpiration, due to less widely opened plant stomata and the resultant increase in stomatal resistance at higher atmospheric CO₂ concentrations. As a result, low cloud cover is decreasing over most of the land surface, reducing planetary albedo and causing more solar radiation to reach the surface, thus further raising temperatures beyond the level of viability for many species. At the same time, the above extreme weather events are causing more water vapor to rise high in the atmosphere, resulting in cirrus clouds that reflect only little sunlight back into space, while trapping more heat (i.e. surface radiation emitted as longwave energy into space). Furthermore, emissions such as dust and soot from wildfires and storms can settle on snow and ice, resulting in faster melting.


Explanation of Quantifying global soil carbon losses in response to warming (1 December 2016) by lead author Thomas Crowther from the Netherlands Institute of Ecology (NIOO-KNAW) and Yale University.

Conclusion

In conclusion, while CO₂ emissions from fossil fuels and industry may have barely grown, levels of greenhouse gases are steadily increasing, if not accelerating. At the same time, extreme weather events are on the rise and there are further factors contributing to cause the land carbon sink to shrink in size. Furthermore, the IPCC appears to have underestimated sensitivity to CO₂ rise.

Rising Temperatures

Without action, temperatures can therefore be expected to rise further, rather than come down from their currently already very high levels, as illustrated by the image below.


The image below shows the temperature rise of the oceans. Temperatures are rising particularly rapidly on the Northern Hemisphere. Much of that heat is carried by the Coriolis force along the Gulf Stream toward the Arctic Ocean.

[ click on images to enlarge ]
This contributes to a huge rise in the temperature of the atmosphere over the Arctic Ocean, as illustrated by the images below. The image directly below shows showing temperature rises up to 10.2°C in the Arctic for October 2016.


The DMI graph below shows daily mean temperature and climate north of the 80th northern parallel, as a function of the day of year.

Red line: 2016 up to November 15, 2016.  -   Green line: climate 1958-2002.

On November 19, 2016, on 00.00 UTC, the Arctic was as much as 7.54°C or 13.57°F warmer than it was in 1979-2000, as illustrated by the image below.



The image below shows the average temperature on November 19, 2016. The Arctic was 7.3°C or 13.14°F warmer than it was in 1979-2000, illustrating the accelerating warming of the Arctic Ocean. The Arctic Ocean in many places shows temperature anomalies at the top end of the scale, i.e. 20°C or 36°F.


Global sea ice

As another reflection of an increasingly warmer world, the combined extent of Arctic and Antarctic sea ice is currently at a record low. On November 12, 2016, combined global sea ice extent was only 23.508 million km².


On November 18, 2016, combined Arctic and Antarctic sea ice extent was only 22.608 million km². That's a fall of 0.9 million km² in six days!


Two images, created by Wipneus with NSIDC data, are added below to further illustrate the situation.

Above image shows global sea ice extent over the years, while the image below shows global sea ice area over the years. For more on the difference between extent and area, see this NSIDC FAQ page.

Some of the consequences of the dramatic global sea ice decline are:
  • More Ocean Heat: Huge amounts of sunlight that were previously reflected back into space are now instead absorbed by oceans.
  • Faster Melt: Decline of the sea ice makes it easier for warm sea water to get underneath glaciers and speed up their flow into the water.
  • Stronger Storms: More open water results in stronger storms, causing rainfall and further decline of the snow and ice cover, as well as greater cloud cover at high altitudes, resulting in more warming.
  • More Methane: Further decline of the snow and ice cover on Greenland and Antarctica in turn threatens to cause increased releases of methane from Greenland and Antarctica, as described in earlier posts such as this one. Furthermore, continued warming of the Arctic Ocean threatens to cause huge eruptions of methane from its seafloor.
Methane

While carbon dioxide emissions get a lot of attention (and they definitely must be cut rapidly and dramatically), the rise of methane is possibly even more worrying. The image below shows historic growth rates of methane (CH4), carbon dioxide (CO₂) and nitrous oxide (N2O).


According to NOAA data, annual mean global methane grew from 2004-2013 by an average of 3.75 ppb per year. In 2014, the growth rate was 12.56 ppb. In 2015, the growth rate was 10.14 ppb. According to the WMO, methane's 2014–2015 absolute increase was 11 ppb. For more on methane, see the methane page.

The situation is dire and calls for comprehensive and effective action, as described in the Climate Plan.


Links

 Greenhouse gas levels and temperatures keep rising
http://arctic-news.blogspot.com/2016/01/greenhouse-gas-levels-and-temperatures-keep-rising.html

 Climate Feedbacks Start To Kick In More
http://arctic-news.blogspot.com/2016/06/climate-feebacks-start-to-kick-in-more.html

 Pursuing Efforts?
http://arctic-news.blogspot.com/2016/10/pursuing-efforts.html

 Methane hydrates
http://methane-hydrates.blogspot.com/2013/04/methane-hydrates.html

 Wildfires in Russia's Far-East
http://arctic-news.blogspot.com/2016/08/wildfires-in-russias-far-east.html

 Methane
http://arctic-news.blogspot.com/p/methane.html



Friday, November 4, 2016

Less sea ice, warmer Arctic Ocean

On November 2, 2016, Arctic sea ice extent was at a record low for the time of the year, i.e. only 7.151 million km².
The currently very low sea ice extent is further dragging down the average annual sea ice extent, which is also at a record low, as illustrated by the image below, from the blog by Torstein Viðdalr.


Not only is Arctic sea ice extent very low, the sea ice is getting thinner and thinner, as illustrated by the image below, by Wipneus, showing the dramatic recent decline of Arctic sea ice thickness.
As the Naval Research Lab 30-day animation below shows, Arctic sea ice isn't getting much thicker, despite the change of seasons.

Naval Research Lab 30-day animation (new model) up to Nov 1, 2016, with forecast up to Nov 9, 2016
In the two videos below, Paul Beckwith further explains the situation.



Paul Beckwith: "Arctic sea ice regrowth is eff'd this year, in fact is truly horrible. As the ice extent, defined as regions with at least 15% ice, tries to expand via sea water freezing, it is melted out by extremely high sea surface temperatures. Then the cooled surface water mixes via wave action with warmer water down to as much as 200 meters and the warm mixtures at the surface continue the process of sea ice melting. Without strong ice regrowth, we will reach the state we are heading to. Namely, zero sea ice. We must break this vicious cycle, by declaring a global climate emergency, and implementing the three-legged-stool solution set."



As global warming raises the temperature of the sea surface and the atmosphere over the sea surface, ever stronger winds develop, in turn resulting in stronger waves and higher amounts of water in clouds.

The image below shows forecasts for November 9, 2016, of waves as high as 13.76 m (green circle, left panel) and of total amounts of water (from surface to space) as much as 1.38 kg/m² (green circle right panel, near Novaya Zemlya).

[ click on images to enlarge ]
High waves make it hard for sea ice to form, while greater evaporation from warmer oceans adds more water vapor to the atmosphere. More water vapor in the atmosphere results more precipitation. Rain can devastate the sea ice, as discussed in an earlier post. Furthermore, snow can inhibit formation of thicker is, as David Barber explains. Also, being a potent greenhouse gas, water vapor will further accelerate warming of the Arctic.

The dire state of the sea ice indicates that the water of the Arctic Ocean is getting warmer and warmer.


On October 31, 2016, the Arctic Ocean was as warm as 17°C or 62.7°F (green circle near Svalbard), or 13.9°C or 25°F warmer than 1981-2011. This indicates how much warmer the water is beneath the surface, as it arrives in the Arctic Ocean from the Atlantic Ocean.

Below is an update of the situation on methane. Contained in existing data is a trend indicating that methane levels could increase by a third by 2030 and could almost double by 2040.


Why is methane so important? On a 10-year timescale, methane causes more warming than carbon dioxide. Unlike carbon dioxide, methane's Global Warming Potential rises as more of it is released. Methane's lifetime can be extended to decades, in particular due to depletion of hydroxyl in the atmosphere.


Ominously, the image below shows that on November 9, 2016, methane levels were very high over the Laptev Sea (solid magenta color north of Siberia). 

The image below shows that methane levels on November 9, 2016, were as high as 2633 parts per billion (at a slightly higher altitude corresponding to a pressure of 469 mb). 
Temperatures over the Arctic Ocean are forecast to remain high, reflecting the very high temperature of the water.


The danger is that, as global warming continues and as the Arctic snow and ice cover keeps shrinking, warming of the Arctic Ocean will speed up and destabilize methane hydrates contained in sediments at its seafloor, triggering huge methane eruptions that will further accelerate warming. This could contribute to make global temperature rise by as much as 10°C or 18°F over the coming decade.

The situation is dire and calls for comprehensive and effective action, as described in the Climate Plan.