Showing posts with label surface. Show all posts
Showing posts with label surface. Show all posts

Monday, April 2, 2018

How much warmer is it now?

The IPCC appears to be strongly downplaying the amount of global warming that has already occurred and that looks set to eventuate over the next decade or so, according to a leaked draft of the IPCC 'Special Report on 1.5°C above pre-industrial'. The 'First Order Draft of the Summary for Policy Makers' estimates that the global mean temperature reached approximately 1°C above pre-industrial levels around 2017/2018.

Let's go over the numbers step by step, by following the image below line by line (click on the image to enlarge it).

NASA's data for the two most recent years for which data are available (2016/2017) show a warming of 0.95°C when using a baseline of 1951-1980 and a warming of 1.23°C when using a baseline of 1890-1910 (left map on image below). In other words, using this earlier baseline results in an additional 0.28°C rise. When using an even earlier baseline, i.e. 1750 or preindustrial, it could be 1.53°C warmer, as discussed in an earlier post.


In other words, merely changing the baseline to preindustrial, as agreed to at the Paris Agreement, can show that we're already above the 1.5°C guardrail that the Paris Agreement had pledged we should not cross.

There's more! As a recent publication points out, most methods that calculate the global temperature use sea surface temperatures. However, doesn't it make more sense to calculate the temperature of the air just above the sea surface? Measuring air temperature at the surface is done in the case of temperatures over land, where one doesn't measure the temperature of the soil or rocks when telling people how warm it is. Since air surface temperatures are slightly higher than sea surface temperatures, the result of looking at air surface temperatures across the globe would be a temperature that is approximately 0.1°C warmer. Furthermore, many areas in the Arctic may not have been adequately reflected in the global temperature, e.g. because insufficient data were available. Since the Arctic has been warming much faster than the rest of the world, inclusion of those areas would add another 0.1°C to the rise. Adding this to the above 1.53°C rise makes that it's already 1.73°C (or 3.11°F) warmer than preindustrial.

Another question is over what period measurements should be taken when assessing whether thresholds have been crossed. When focusing on temperatures during specific months, the rise could be much higher than the annual average. So, does it make more sense to look at a monthly peak rather than at a long-term average?

When building a bridge and when calculating what load the bridge should be able to handle, it makes sense to look at peak traffic and at times when a lot of heavy trucks happen to be on the bridge. That makes a lot more sense than only looking at the average weight of cars driving over the bridge during a period of - say - one, two or thirty years.


Accordingly, the right panel of the top image shows numbers for February 2016 when temperature anomalies were particularly high. When looking at this monthly anomaly, we are already 2.37°C (or 4.27°F) above preindustrial, i.e. well above the 2°C guardrail that the Paris Agreement had pledged we should definitely not cross.

Should the temperature rise be calculated using a longer period? The IPCC appears to have arrived at its temperature rise estimate by using an extrapolation or near term predictions of future warming so that the level of anthropogenic warming is reported for a 30 year period centered on today.

The image below, from an earlier post, shows global warming for a 30-year period centered on January 2018, using NASA 2003 to January 2018 LOTI anomalies from 1951-1980, adjusted by 0.59°C to cater for the rise from preindustrial to 1951-1980, and with a polynomial trend added.


If above trendline is adjusted by a further 0.2°C, by shifting to air temperatures instead of sea surface temperatures, and by better reflecting Arctic temperatures, then the trendline looks set to cross the 2°C guardrail in 2018. So, will Earth cross 2°C in 2018?


Above images illustrate the importance of what's going to happen next. The temperature rise up until now may well be dwarfed by what's yet to come and the outlook may well be even worse than what most fear will eventuate. The image below, from an earlier post, shows a steep rise from 2016 to 2026, due to the combined impact of the warming elements listed in the left box of the image below.


Meanwhile, the rise in carbon dioxide levels appears to be accelerating, as illustrated by the images below.


Indeed, despite pledges made at the Paris Agreement to limit the temperature increase to 1.5°C above pre-industrial, the rise in CO₂ since preindustrial, i.e. 1750, still appears to be accelerating.


On March 18, 2018, the sea surface temperature near Svalbard (at the green circle) was 16.7°C or 62.1°F, i.e. 14.7°C or 26.4°F warmer than the daily average during the years 1981-2011.


On March 30, 2018, methane levels as high as 2624 parts per billion were recorded.


On April 1, 2018, methane levels as high as 2744 parts per billion were recorded.



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


Links

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Extinction
https://arctic-news.blogspot.com/p/extinction.html

• How much warming have humans caused?
https://arctic-news.blogspot.com/2016/05/how-much-warming-have-humans-caused.html

• IPCC seeks to downplay global warming
https://arctic-news.blogspot.com/2018/02/ipcc-seeks-to-downplay-global-warming.html

• 2016 well above 1.5°C
https://arctic-news.blogspot.com/2017/01/2016-well-above-1.5c.html

• Interpretations of the Paris climate target, by Andrew Schurer et al.
https://www.nature.com/articles/s41561-018-0086-8


Saturday, September 3, 2016

Action must be taken now


Some of the world's most preeminent climate scientists, all experts with many decades of experience in their respective field, are warning that effective action must be taken now to avoid catastrophe.

These scientists, and many others, have made valuable and much-appreciated contributions to the Arctic-news blog over the years [note: contributors each express their own views in posts and may or may not endorse other content of this blog].

Sam Carana, editor of this blog, has for years supported the calls of these scientists, also discussing and sharing their calls at facebook groups such as Arctic-News, Electric TransportRenewables and Climate Alert.


Furthermore, Sam Carana has called for specific action for years, including support for biochar, preferably through feebates. More specifically, Sam Carana recommends that revenues raised from fees imposed on sales of livestock products, nitrogen fertilizers and Portland cement are used to fund support for soil supplements, as illustrated by above image. For more on biochar, see this blog and this facebook group.

For years, Sam Carana has also called for more R&D in specific areas of geo-engineering. For more on this, see this blog and this facebook group.

More generally, Sam Carana advocates the Climate Plan, which calls for a global commitment to parallel lines of action while seeking to delegate implementation to local communities, preferably through effective policies such as local feebates.

This blog has had some success in spreading this message. To date, Sam Carana has received 82,327,368 views at Google plus (see screenshot on the right), while this blog has received 3,255,445 views (see update of views in the panel further on the right).

Your continued support is needed to share this message, so please join one or more of the above-mentioned groups, and share and like the images of this post in emails, on facebook and other social media.

Regarding the urgency to act, the images below give an update on the terrifying situation in the Arctic, where the sea ice is disappearing fast.

The decline of the snow and ice cover in the Arctic goes hand in hand with rising sea surface temperatures that contribute to sea ice getting ever thinner.

The image on the right show Arctic sea ice on September 1, 2016, with thickness in meters.

The warming of the oceans is illustrated by the images below.

The image directly below shows sea surface temperature (left) and anomalies compared to 1981-2011 (right).


The image below also shows sea surface temperature anomalies, this time compared to 1971-2000.


Global warming has hit the Arctic particularly hard over the past 365 days, with anomalies exceeding the top end of the scale over most of the Arctic Ocean, as illustrated by the image below.


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

Saturday, October 10, 2015

Arctic Sea Ice 2015 - update 11

Arctic sea ice extent has been growing rapidly recently. The image below shows extent up to October 9, 2015 (marked by red dot).


Below is a comparison of sea ice thickness as on October 6, for the years (from left to right) 2012, 2013, 2014 and 2015. The comparison shows that decline has been strongest where sea ice used to be the thickest, i.e. over 3 meters thick.


One of the reasons why the thickest Arctic sea ice has declined so dramatically over the years is the rising ocean heat that is melting the sea ice from underneath. The image below illustrates the situation on October 5, 2015, when sea surface temperature anomalies were as high as 6.4°C, 7.4°C and 7.3°C (11.5°F 13.2°F and 13.1°F) off the North American coast, and as high as 9.4°C (16.8°F) near Svalbard.


Water temperatures are very high in the Arctic, as further illustrated by the image below showing Arctic sea surface temperature anomalies as at October 9, 2015.



Rising ocean heat is further illustrated by the graph below, showing August sea surface temperature anomalies on the Northern Hemisphere over the years.
The situation is very dangerous, due to feedbacks and their interaction. The thicker sea ice used to act as a buffer, consuming ocean heat in the melting process. Without thicker sea ice, ocean heat threatens to melt the sea ice from below right up to the surface, causing the entire sea ice to collapse. As the sea ice declines, more open water will give rise to stronger winds and waves.

Furthermore, sunlight that was previously reflected back into space will instead be absorbed by the water, causing rapid rise of the temperature of the water. In places such as the East Siberian Arctic Shelf, the water is on a average only 50 m deep, so warmer water is able to reach the seafloor more easily there. As ocean heat keeps rising, there's a growing risk that heat will reach the Arctic Ocean seafloor and destabilize methane hydrates in sediments at the Arctic Ocean seafloor.

The image below shows a non-linear trend that is contained in the temperature data that NASA has gathered over the years, as described in an earlier post. A polynomial trendline points at global temperature anomalies of over 4°C by 2060. Even worse, a polynomial trend for the Arctic shows temperature anomalies of over 4°C by 2020, 6°C by 2030 and 15°C by 2050, threatening to cause major feedbacks to kick in, including albedo changes and methane releases that will trigger runaway global warming that looks set to eventually catch up with accelerated warming in the Arctic and result in global temperature anomalies of 16°C by 2052.

[ click on image to enlarge ]
The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.

Comparison of sea ice thickness on October 6, for the years (from left to right) 2012, 2013, 2014 and 2015, shows that...

Posted by Sam Carana on Saturday, October 10, 2015

Friday, September 25, 2015

Warming Arctic Ocean Seafloor Threatens To Cause Huge Methane Eruptions

Rapidly growing 'Seal' over Arctic Ocean



Arctic sea ice extent and especially concentration are now growing rapidly, as illustrated by the Naval Research Lab animation on the right.

This means that the sea ice is effectively sealing off the water of the Arctic Ocean from the atmosphere, reducing the chances of transfer of ocean heat from the water to the atmosphere. Conversely, the risk grows that ocean heat will reach the seafloor.

Furthermore, this seal makes that less moisture evaporates from the water, which together with the change of seasons results in lower hydroxyl levels at the higher latitudes of the Northern Hemisphere, in turn resulting in less methane being broken down in the atmosphere over the Arctic.

Rising Ocean Heat



Water temperatures are very high in the Arctic. Above image shows Arctic sea surface temperature anomalies as at September 24, 2015. The risk of ocean heat reaching the Arctic Ocean seafloor has increased significantly over the years, due to rising ocean heat, as illustrated by the graph below, showing August sea surface temperature anomalies on the Northern Hemisphere over the years. 

[ from the earlier post: August 2015 Had Highest Sea Surface Temperature on Record ]
Ocean heat is increasing because people's emissions are making the planet warmer and more than 93% of the extra heat goes into the oceans.

Ocean temperatures have been measured for a long time. Reliable records go back to at least 1880. Ever since records began, the oceans were colder than they are now. Back in history, there may have been higher temperature peaks - the last time when it was warmer than today, during the Eemian Period, peak temperature was a few tenths of a degree higher than today. In many ways, however, the situation now already looks worse than it was in the Eemian. "The warm Atlantic surface current was weaker in the high latitude during the Eemian than today", says Henning Bauch. Furthermore, carbon dioxide levels during the Eemian were well under 300 ppm. So, there could well have been more pronounced seasonal differences then, i.e. colder winters that made that the average ocean temperature didn't rise very much, despite high air temperature in summer. By contrast, today's high greenhouse levels make Earth look set for a strong ocean temperature rise.

And indeed, this is illustrated by above image, showing a polynomial trendline that points at a rise of almost 2°C by 2030. This trendline is contained in ocean temperature data from 1880 for the August Northern Hemisphere sea surface temperature anomalies.

Cold Freshwater 'Lid' on North Atlantic



Note that the above ocean temperature graph and the above video only show sea surface temperatures. Underneath the surface, water can be even warmer. The Gulf Stream reaches its maximum temperatures off the North American coast in July. It can take some four months for this heat to travel along the Gulf Coast and reach destinations farther in the Arctic Ocean. Water warmed up off Florida in July may only reach waters beyond Svalbard by October or November.

The image below shows that on August 22, 2015, at a location near Florida marked by the green circle, sea surface temperatures were as high as 33.4°C (92.1°F), an anomaly of 3.8°C (6.8°F).


The image below shows sea surface temperatures on August 22, 2015, as an indication of the huge amount of ocean heat has accumulated in the Atlantic Ocean off the coast of North America.


The huge amounts of energy entering the oceans translate into higher temperatures of the water and of the air over the water, as well as higher waves and stronger winds.

Ocean heat carried by the Gulf Stream from Florida via the North Atlantic into the Arctic Ocean.
The image on the left shows that on August 25, 2015, sea surface temperatures near Svalbard were recorded as high as 17.3°C (63.1°F), as marked by the green circle, a 12.1°C (21.8°F) anomaly.

This indicates that ocean heat did reach that location from underneath the sea surface. In other words, subsurface temperatures of the water carried along by the Gulf Stream can be substantially higher than temperatures of the water at the surface, and this can be the case for the water all the way from the coast of North America to the Arctic Ocean.

The Gulf Stream keeps pushing much of this very warm water north, into the Arctic Ocean, where it threatens to unleash huge methane eruptions from the Arctic Ocean seafloor.

The combination image below shows the Gulf stream carrying warm water from the coast of North America into the Arctic Ocean on September 12, 2015, and sea surface reaching temperatures as high as 14.6°C (58.3°F) that day at a location near Svalbard (marked by green circle), an 9.8°C (17.6°F) anomaly

[ click on image to enlarge ]
The combination image below shows that sea surface temperature anomalies still are very high. The left panel shows that anomalies on September 25, 2015 were as high as +6°C (+10.8°F) in the North Atlantic (location marked by green circle), compared to 1901-2011. The right panel shows anomalies on September 26, 2015, in the North Atlantic of +0.81°C (+1.46°F) and in the North Pacific of +1.02°C (+1.84°F), compared to 1971-2000.


Below is an update on the situation. On October 5, 2015, sea surface temperature anomalies were as high as 6.4°C, 7.4°C and 7.3°C (11.5°F 13.2°F and 13.1°F) off the North American coast, and as high as 9.4°C (16.8°F) near Svalbard.


Speed of surface water was as high as 1.6 m/s (3.6 mph) on October 5, 2015. This wasn't as high as some of the speeds reached earlier in the year (a speed of 2.16 m/s or 4.7 mph was recorded on August 15, 2015), but it does indicate how strong the Gulf Stream still is at this time of year. Water speed slows down as the Gulf Stream progresses toward the Arctic Ocean. While speeds as high as 0.22 m/s and 0.24 m/s (0.5 mph) were recorded near Svalbard and Norway, overall speed was a lot lower in this part of the Atlantic.

What is making the situation worse is depicted in the images below. From 2012, huge amounts of freshwater have run off Greenland, with the accumulated freshwater now covering a huge part of the North Atlantic, as illustrated by the image below. 


Since it's freshwater that is now covering a large part of the surface of the North Atlantic, it will not easily sink in the very salty water that was already there. The water in the North Atlantic was very salty due to the high evaporation, which was in turn due to high temperatures and strong winds and currents. As said, freshwater tends to stay on top of more salty water, even though the temperature of the freshwater is low, which makes this water more dense. The result of this stratification is less evaporation in the North Atlantic, and less transfer of ocean heat to the atmosphere, and thus lower air temperatures than would have been the case without this colder surface water.


As meltwater accumulates at the surface of the North Atlantic, will it slow down the Gulf Stream?

More elongated curves and eddies forming where the meltwater meets the Gulf Stream appears to make that it will indeed take longer for surface water to travel from the coast of North America to the Arctic Ocean. However, the speed reached within such eddies may actually be higher. After all, the amount of extra heat that enters the oceans keeps growing and this extra energy will likely translate into warmer water carried in greater volumes and at higher speed by the Gulf Stream underneath the surface of the North Atlantic into the Arctic Ocean, be it that the more curved patterns of the currents will increase the overall time it takes for water to travel the distance, especially at the surface.

Importantly, as global warming continues to heat up the oceans, the accumulated freshwater at the surface of the North Atlantic makes that less ocean heat can be transferred from the water to the atmosphere there, i.e. the freshwater is acting like a lid. Similarly, the Arctic sea ice is acting as a seal over the Arctic Ocean, as seasons change. In conclusion, the highest temperatures of the water of the Arctic Ocean, especially at greater depth, are yet to be reached this year.


Above image illustrates that, while Arctic sea water at the surface reaches its highest temperatures in the months from July to September, water at greater depth reaches its highest temperatures only in October through to the subsequent months.

Methane Eruptions from Arctic Ocean Seafloor

In the Arctic Ocean, this more salty newly-arriving warm water will tend to dive under the freshwater that has formed from the melting of sea ice over the past few months. The danger is thus that warmer water will be pushed into the Arctic Ocean at lower depth, and that it will reach the seafloor of the Arctic Ocean.

Huge amounts of methane are contained in sediments on the Arctic Ocean seafloor. Ice acts like a glue, holding these sediments together and preventing destabilization of methane hydrates. 

Pingos and conduits. Hovland et al. (2006)
Warmer water reaching these sediments can penetrate them by traveling down cracks and fractures in the sediments, and reach the hydrates. The image on the right, from a study by Hovland et al., shows that hydrates can exist at the end of conduits in the sediment, formed when methane did escape from such hydrates in the past. Heat can travel down such conduits relatively fast, warming up the hydrates and destabilizing them in the process, which can result in huge abrupt releases of methane.

Heat can penetrate cracks and conduits in the seafloor, destabilizing methane held in hydrates and in the form of free gas in the sediments.

Elsewhere, methane hydrates will typically be located at great depth, making it more difficult for ocean heat to reach them. In the Arctic, much of the water is very shallow. The East Siberian Arctic Shelf (ESAS) is on average only 50 m deep, making it easier for heat to reach the seafloor and also making that methane that escapes will have to travel through less water, reducing the chances that methane will be broken down by microbes on the way up through the water. Furthermore, hydroxyl levels are very low over the Arctic, making that the methane will not quickly be broken down in the atmosphere over the Arctic either.

The big melt in Greenland and the Arctic in general is causing further problems. Isostatic adjustment following melting can contribute to seismic events such as earthquakes, shockwaves and landslides that can destabilize methane hydrates contained in sediments on the Arctic Ocean seafloor.


Above image shows methane levels as high as 2554 parts per billion, on the morning of September 23, 2015, in the bottom panel, and strong methane releases over the ESAS, as indicated by the solid magenta-colored areas in the top panel, on the afternoon of the previous day at lower altitude. These are indications of methane releases from the seafloor of the Arctic Ocean. Strong winds over the ESAS, as the image below shows, may have contributed, by mixing warm water down to the seafloor.


On the morning of September 25, 2015, methane reached levels as high as 2629 ppb, while mean global level reached a record high 1846 ppb. The video below, created with Climate Reanalyzer images,  shows strong winds over the Arctic for the period September 26 to October 3, 2015.


The video below, created by Cameron Forge with Climate Reanalyzer images, shows Arctic air temperature anomalies end September - early October, 2015.



Air Temperature Rise

NOAA data show that the year-to-date land surface temperature in July was 1.47°C above the 20thcentury average on the Northern Hemisphere in 2015. A polynomial trendline based on these data points at yet another degree Celsius rise by 2030, on top of the current level, which could make it 3.27°C warmer than in 1750 for most people on Earth by the year 2030, as illustrated by the image below.

Will it be 3.27°C warmer by the year 2030?
The image below shows a non-linear trend that is contained in the temperature data that NASA has gathered over the years, as described in an earlier post. A polynomial trendline points at global temperature anomalies of over 4°C by 2060. Even worse, a polynomial trend for the Arctic shows temperature anomalies of over 4°C by 2020, 6°C by 2030 and 15°C by 2050, threatening to cause major feedbacks to kick in, including albedo changes and methane releases that will trigger runaway global warming that looks set to eventually catch up with accelerated warming in the Arctic and result in global temperature anomalies of 16°C by 2052.
[ click on image to enlarge ]
The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.



In the Arctic Ocean, the more salty newly-arriving warm water will tend to dive under the freshwater that has formed...
Posted by Sam Carana on Friday, September 25, 2015

Tuesday, September 22, 2015

Arctic Sea Ice 2015 - Update 10

It looks like sea ice has passed its minimum extent for the year 2015, as illustrated by the image below.


There are some differences between the various websites measuring extent, such as to whether the 2015 low was the third or fourth lowest. Japanese measurements show that sea ice extent was 4.26 million square km on September 14, 2015, i.e. lower than the 2011 minimum of 4.27 million square km, as illustrated by the image below.


Meanwhile, the Polar Science Center at the University of Washington has announced that Arctic sea ice volume minimum was reached on September 12, 2015, with a total volume of 5,670 cubic km. The image below shows a polynomial trendline based on their annual Arctic sea ice volume minima, including this volume for 2015.


Importantly, the sea ice in many places is now less thick than it was in 2012, as illustrated by the image below, showing sea ice thickness on September 27, 2012 (panel left) and a forecast for September 27, 2015 (panel right).


The reason for the dramatic decrease in thickness of the multi-year sea ice is ocean heat, as illustrated by the image below, showing sea surface temperature anomalies in the Arctic as at September 21, 2015.


The water of the Arctic Ocean is very warm, not only at the surface, but even more so underneath the surface. What has contributed to this situation is described by the image below. From 2012, huge amounts of fresh water have run off Greenland, with the accumulated fresh water now covering a huge part of the North Atlantic.

Since it's fresh water that is now covering a large part of the surface of the North Atlantic, it will not easily sink in the very salty water that was already there. The water in the North Atlantic was very salty due to the high evaporation, which was in turn due to high temperatures and strong winds and currents. As said, fresh water tends to stay on top of more salty water, even though the temperature of the fresh water is low, which makes this water more dense. The result of this stratification is less evaporation in the North Atlantic, and less transfer of ocean heat to the atmosphere, and thus lower air temperatures than would have been the case without this colder surface water.


Meanwhile, global warming continues to heat up the oceans, while less of this ocean heat can now be transferred from the water to the atmosphere in the North Atlantic, since the fresh water is acting like a lid.

The danger is thus that warmer water will be pushed into the Arctic Ocean at lower depth, and that it will reach the seafloor of the Arctic Ocean where huge amounts of methane are contained in sediments. Ice acts like a glue, holding these sediments together and preventing destabilization of methane hydrates. Warmer water reaching these sediments can penetrate them by traveling down cracks and fractures in the sediments, and reach the hydrates.

The big melt in Greenland and the Arctic in general is causing further problems. Isostatic adjustment following melting can contribute to seismic events such as earthquakes, shockwaves and landslides that can destabilize methane hydrates contained in sediments on the Arctic Ocean seafloor.

In the video below, by Nick Breeze, Professor Peter Wadhams discusses the situation.



The situation is dire and calls for comprehensive and effective action as discussed at the Climate Plan.


The water of the Arctic Ocean is very warm, not only at the surface, but even more so underneath the surface. What has...
Posted by Sam Carana on Tuesday, September 22, 2015