Arctic News: ocean heat

Showing posts with label ocean heat. Show all posts

Friday, January 25, 2019

Accelerating growth of carbon dioxide in the atmosphere

People may not have thought that growth in carbon dioxide (CO₂) levels in the atmosphere would accelerate, when pledges were made in 2015 at the Paris Agreement to take efforts to keep the temperature rise under 1.5°C compared to preindustrial.

Yet, on January 21, 2019, hourly average CO₂ levels well above 414 ppm were recorded at Mauna Loa, Hawaii, the highest levels since such measurements started. A daily average level of 413.86 ppm was recorded on January 22, 2019.

A recent Met Office forecast expects monthly averages to reach a level of 414.7 ppm in May 2019. The forecast expects annual average CO₂ levels at Mauna Loa to be 2.75 ppm higher in 2019 than in 2018. That figure is virtually on the trendline depicted below.

The trend in above image is calculated with NOAA 1959-2017 growth data, with an estimate for 2018 calculated by Sam Carana with NOAA January 2017-November 2018 data (orange dot), and with this Met Office forecast used for 2019 (purple dot).

Strong CO₂ growth is forecast for 2019, due to a number of factors including rising emissions, the added impact of El Niño and less uptake of carbon dioxide by ecosystems. A recent study warns that global warming will enhance both the amplitude and the frequency of eastern Pacific El Niño events and associated extreme weather events. Another recent study warns that, while the terrestrial biosphere now absorbs some 25% of CO₂ emissions by people, the rate of land carbon uptake is likely to fall with reduced soil moisture levels in a warmer world. Furthermore, forest fires will increase as temperatures rise, as soils get more dry and as winds increase in strength, resulting in further increases of CO₂ emissions.

The warming impact of CO₂ can be expected to increase over the next ten years, the more so since the warming impact of CO₂ reaches a peak ten years after emission. In conclusion, CO₂ can cause a global temperature rise of 0.5°C over the next ten years.

Ocean Heat

La Niña has kept much heat in oceans in 2018. Not surprisingly, 2018 was the hottest year for our oceans since global records began in 1958.

As an indication how much heat is contained in the North Atlantic, very high sea surface temperatures did show up recently off the coast of North America, with anomalies on January 23, 2019, as high as 12.6°C or 22.6°F (compared to 1981-2011, green circle on the image on the right).

That day, sea surface temperatures near Svalbard were as high as 18.3°C or 64.9° (green circle, image right). The Gulf Stream carries ocean heat to the Arctic Ocean and it can take a couple of months for this heat to reach the Arctic Ocean and contribute to melting of the sea ice.

So, Arctic sea ice is expected to be invaded by ocean heat from below in 2019, while El Niño will cause high temperatures over the Arctic, melting the sea ice from above.

Furthermore, rivers that end in North America and Siberia can be expected to carry much warm water into the Arctic Ocean.

The image below shows surface air temperature forecasts for February 1, 2019, 15:00 UTC. Low temperatures show up many place on the Northern Hemisphere, such as -44.5°C or -48.2°F in Siberia, -44°C or -47.1°F in Greenland and -40.8°C or -41.4°F near Hudson Bay.

[ NOAA Climate.gov cartoon by Emily Greenhalgh ]

These low temperatures are the result of global warming. As the Arctic warms up faster than the rest of the world, the temperature difference between the North Pole and the Equator narrows, making the jet stream wavier, thus enabling cold air from the Arctic to descend further south.

As the jet stream gets wavier, more warm air can also enter the Arctic from the south. Above image also shows that surface air temperatures near Svalbard are forecast as high as 5.2°C or 41.4°F, illustrating how warm the air can be close to the North Pole, at a time of year when virtually no sunlight reaches that area.

Furthermore, as oceans get warmer, the temperature difference between land and oceans increases in Winter. This larger temperature difference results in stronger winds that can carry more warm and moist air inland, e.g. into the U.S., as illustrated by the cartoon. Stronger winds can also carry more warm and moist air into the Arctic and can speed up the flow of sea currents, causing warm and salty water to reach the sea ice and speed up its decline.

The sea surface is warming up strongly in this area near Svalbard, as the water underneath the surface of the North Atlantic can be much warmer than the water at the surface, and warm water is coming to the surface in line with a rise in the seafloor in this area, as discussed in earlier posts such as this one and this one.

Methane hydrates

With sea ice at a low, it won't be able to act as a buffer to absorb heat for long. One danger is that, as more heat arrives in the Arctic and as the sea ice melts away, the sea ice will no longer be able to act as a buffer absorbing ocean heat any longer, and ocean heat will instead reach sediments at the seafloor of the Arctic Ocean.

[ The Buffer has gone, feedback #14 on the Feedbacks page ]

Joint impact

[ For details, see the Extinction page ]

The joint impact of all this is terrifying. Ocean heat that reaches sediments at the seafloor of the Arctic Ocean can destabilize hydrates, resulting in eruptions of huge amounts of methane. This alone can cause a global temperature rise of 1.1°C in a matter of years.

A lot of this has not been accounted for by the IPCC, i.e. the recent increases in CO₂ emissions, increases in methane releases, increases in further emissions such as nitrous oxide and black carbon, albedo changes due to decline in the snow and ice cover and associated changes such as jet stream changes, more permafrost melting and stronger impacts of future El Niño events.

The image on the right shows the joint impact of the warming elements that threaten to eventuate over the next few years and that could result in a rapid 10°C or 18°F global temperature rise by 2026 or even earlier. Keep in mind that global biodiversity will have collapsed once temperatures have risen by 5°C.

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

Links

• Faster CO₂ rise expected in 2019
https://www.metoffice.gov.uk/news/releases/2019/2019-carbondioxide-forecast

• Increased variability of eastern Pacific El Niño under greenhouse warming, by Wenju Cai et al.
https://www.nature.com/articles/s41586-018-0776-9

• El Niño events will intensify under global warming, by Yoo-Geun Ham
https://www.nature.com/articles/d41586-018-07638-w

• Large influence of soil moisture on long-term terrestrial carbon uptake, by Julia Green et al.
https://www.nature.com/articles/s41586-018-0848-x

• 2018 Continues Record Global Ocean Warming, by Lijing Cheng et al.
https://link.springer.com/article/10.1007/s00376-019-8276-x

• Are record snowstorms proof that global warming isn’t happening?
https://www.climate.gov/news-features/climate-qa/are-record-snowstorms-proof-global-warming-isn%E2%80%99t-happening

• Co-extinctions annihilate planetary life during extreme environmental change, by Giovanni Strona and Corey Bradshaw
https://www.nature.com/articles/s41598-018-35068-1

• Dangerous situation in Arctic
https://arctic-news.blogspot.com/2018/11/dangerous-situation-in-arctic.html

• Accelerating Warming of the Arctic Ocean
https://arctic-news.blogspot.com/2016/12/accelerating-warming-of-the-arctic-ocean.html

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

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

Saturday, April 11, 2015

Arctic Sea Ice At Record Low On April 9 2015

On April 9, 2015, Arctic sea ice extent was only 14.051 square km, a record low for the time of the year, as illustrated by the image below.

Temperature anomalies at the top end of the scale (20°C, or 36°F) are hitting the Arctic Ocean in many places, as illustrated by the forecast below, showing an overall anomaly of +3.19°C for the Arctic for April 11, 2015, despite low temperatures over Greenland.

The situation is very worrying, the more so since a huge amount of ocean heat is lining up to be carried into the Arctic Ocean by the Gulf Stream. On April 10, 2015, sea surface temperatures of 24.1°C were recorded off the North American coast (green circle), a +12.5°C anomaly, as the image below shows.

Malcolm Light comments: In this inverted blowup of the high temperature region you can see the expanded effect of methane hydrate detabilization along the Gakkel Ridge and the high temperatures caused by the onshore methane eruption vents (image below).

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

On April 9, 2015, Arctic sea ice extent was only 14.051 square km, a record low for the time of the year. From the post ...
Posted by Sam Carana on Saturday, April 11, 2015

Sunday, November 30, 2014

Another Heatwave Hits Arctic

As parts of Canada, Greenland and Russia are hit by -40 degrees temperatures (anomalies at the bottom end of the scale), parts of the Arctic are experiencing temperatures above freezing (anomalies at the top end of the scale), as illustrated by the image below.

[ click on image to enlarge ]

Temperatures in the Arctic are much higher than they used to be and this situation further accelerates warming in the Arctic, due to a number of feedbacks.

One such feedbacks has been coined the ‘open doors feedback’. Indeed, the situation is much like leaving the fridge door open. This allows cold air to more easily move out of the fridge, i.e. the Arctic, resulting in the cold temperatures over North America that have received extensive news coverage in the media. At the same time, warm air can move more easily into the fridge, i.e. the Arctic, and this is one of the reasons why the Arctic is hit by temperatures that are so much higher than what used to be normal.

The situation has been described in a number of earlier posts such as this one, as well in a recent interview with Jennifer Francis. As the Arctic warms more rapidly than the rest of the world, there's less temperature difference between the Arctic and the equator, resulting in the jet stream going around the globe at a lower speed with more elongated loops.

The left chart on above image shows such an elongated loop going north along the east coast of Greenland, then bending before Scandinavia and moving over the north of Greenland, then going around the North Pole and moving back to Scandinavia. This loop is not very visible on the chart, because the jet stream moves faster along straight tracks, and this chart highlights wind speed more than it highlights the path of the jet stream. Yet, the shape of this loop is very important, as it traps warmer air north of Greenland.

BTW, a weaker jet stream also elevates the chance of heat waves elsewhere, which can indirectly warm up the Arctic. Examples of this are heat waves over the Gulf Stream as it crosses the Atlantic Ocean, resulting in warmer water being carried into the Arctic Ocean, and heat waves over Siberia and North America, resulting in warming up of rivers that end in the Arctic Ocean.

Anyway, to get back to the current heatwave, there are a number of reasons why temperatures in the Arctic are so high at the moment. One of the biggest reasons is ocean heat, which has reached very high levels, especially in the North Atlantic, while the Gulf Stream keeps transporting warmer water from the North Atlantic into the Arctic Ocean (i.e. water that is warmer than the water in the Arctic Ocean). This warms up the seafloor of the Arctic Ocean, resulting in methane erupting from the seafloor, with a strong immediate local warming impact in the Arctic, thus further accelerating warming in the Arctic in another one of these self-reinforcing feedback loops, as pictured in the image below.

Further feedbacks that accelerate warming in the Arctic are discussed at the feedbacks page.

Without effective and comprehensive action, these feedbacks threaten to lead to runaway warming, i.e. abrupt climate change causing mass death and destruction, and resulting in extinction at massive scale, as depicted in the image below and as described in this earlier post.

In conclusion, the situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan blog.

Post by Sam Carana.

Sunday, November 23, 2014

IPCC too conservative?

Earlier this month, the Intergovernmental Panel on Climate Change (IPCC) released its 5th Assessment Report (AR5), stating that: "Surface temperature is projected to rise over the 21st century under all assessed emission scenarios. It is very likely that heat waves will occur more often and last longer, and that extreme precipitation events will become more intense and frequent in many regions. The ocean will continue to warm and acidify, and global mean sea level to rise. Many aspects of climate change and associated impacts will continue for centuries, even if anthropogenic emissions of greenhouse gases are stopped. The risks of abrupt or irreversible changes increase as the magnitude of the warming increases."

That does sound scary. So, what would happen if the IPCC's projections are too conservative? Could humans, together with many other species, go extinct within the next few decades? What are the risks that this could eventuate? Below follows an assessment using graphics by Sam Carana.

1. Ocean Heat

Below is what the IPCC says:

Below is a graph produced by Sam Carana, based on NOAA data. For more background, see this earlier post.

2. Sea level Rise

The image below shows what the IPCC says.

If ocean heat will continue to rise as pictured in the image by Sam Carana, then thermal expansion alone will cause more sea level rise than foreseen by the IPCC. Furthermore, extensive melting on Antarctica and Greenland can result in additional sea level rise. Below is a sea level rise graph produced by Sam Carana, based on NASA/GSFCs data, as discussed in this earlier post.

3. Arctic Sea Ice

The image below shows what the IPCC says.

If ocean heat will continues to rise as pictured in the image by Sam Carana, then Arctic sea ice will disappear much earlier than anticipated by the IPCC. An exponential trendline based on sea ice volume observations shows that sea ice looks set to disappear in 2019, while disappearance in 2015 is within the margins of a 5% confidence interval, reflecting natural variability.

A linear trend would be inappropriate, given the growing impact of feedbacks that can each be expected to reinforce sea ice decline, while there can also be interaction between these feedbacks, further accelerating sea ice decline. Albedo change is one such feedback, but there are numerous other ones, such as storms that have more chance to grow stronger as the area with open water increases.

In conclusion, an exponential trendline is more appropriate than a linear trendline, as also illustrated by above comparison, which shows that a linear trendline has 9 years fall outside its 95% confidence ionterval, versus 4 years for an exponential trendline, as discussed at the FAQ page.

Rapid decline of the snow and ice cover on the Northern Hemisphere is furthermore supported by rapidly rising surface temperatures over the Arctic, as well as greater intensity of heatwaves. Below is what the IPCC says on this.

Before further discussing surface temperatures, let's look into one of the feedbacks that could hugely increase temperatures, methane.

4. Methane

The IPCC appears to underestimate of the amount of methane that is contained in sediments under the Arctic Ocean and prone to be released as temperatures rise, as discussed in this earlier post and at this page. In an absurd articulation of contradictionary logic, the IPCC writes on the one hand that there is little consensus on the likelihood of abrupt changes over the 21st century, while on the other hand the IPPC declares with 'high confidence' that it is very unlikely that methane from clathrates will undergo catastrophic release during the 21st century, as discussed in this earlier post.

The image below, based on data from the IPCC and the World Metereological Organization (WMO), with an added observation from a NOAA MetOp satellite image, illustrates the recent rise of methane levels and the threat that methane levels will continue to rise rapidly.

When looked at from a longer range of years, above image fits in the black square on the image below.

As ocean heat keeps increasing and warming in the Arctic keeps accelerating due to feedbacks such as Arctic sea ice decline, huge methane eruptions from the seafloor of the Arctic Ocean threaten to push up methane levels even further. The image below shows exponential rise based on data of East Siberian Arctic Shelf (ESAS) releases alone, as discussed in an earlier post.

Non-linear rise is supported by the fact that methane's lifetime increases as more methane enters the atmosphere.

5. Surface Temperatures

The IPCC expects that, worst case, global average temperature could rise by 13 degrees Celsius by 2300, as illustrated by the image below.

The situation could be much worse than foreseen by the IPCC, due to the non-linear way feedbacks can hugely increase temperature rises.

The threat is that such rapid temperature rises will appear at first in hotspots over the Arctic and eventually around the globe, while also resulting in huge temperature swings that could result in depletion of supply of food and fresh water, as further illustrated by the above image, from an earlier post, and the image below, from another earlier post.

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