Will humans be extinct by 2026?
In the Arctic, vast amounts of carbon are stored in soils that are now still largely frozen. As temperatures continue to rise and soils thaw, much of this carbon will be converted by microbes into carbon dioxide or methane, adding further greenhouse gases to the atmosphere.
In addition, vast amounts of methane are stored in sediments under the Arctic Ocean seafloor, in the form of methane hydrates and free gas. As temperatures rise, these sediments can get destabilized, resulting in eruptions of huge amounts of methane from the seafloor. Due to the abrupt character of such releases and the fact that many seas in the Arctic Ocean are shallow, much of the methane will then enter the atmosphere without getting broken down in the water.
What makes the situation so dangerous is that huge eruptions from the seafloor of the Arctic Ocean can happen at any time. We can just count ourselves lucky that it hasn't happened as yet. As temperatures continue to rise, the risk that this will happen keeps growing.
One such feedback is the retreat of the sea ice, which in turn makes the Arctic Ocean heat up even more, as much sunlight that was previously reflected back into space by the sea ice, instead gets absorbed by the water when the sea ice is gone.
Without sea ice, storms can also develop more easily. Storms can mix warm surface waters all the way down to the bottom of shallow seas, reaching cracks in sediments filled with ice. This ice has until now acted as a glue, holding the sediment together. As the ice melts, sediments can become destabilized by even small differences in temperature and pressure that can be triggered by earthquakes, undersea landslides or changes in ocean currents.
As a result, huge amounts of methane can erupt from the seafloor of the Arctic Ocean and once this occurs, it will further raise temperatures, especially over the Arctic, thus acting as another self-reinforcing feedback loop that again makes the situation even worse in the Arctic, with higher temperatures causing even further methane releases, in a vicious cycle leading to runaway global warming.
Such a temperature rise in the Arctic will not stay within the borders of the Arctic. It will trigger huge firestorms in forests and peatlands in North America and Russia, adding further emissions including soot that can settle on mountains, speeding up the melting of glaciers and threatening to stop the flow of rivers that people depend on for their livelihood.
These developments can take place at such a speed that adaptation will be futile. More extreme weather events can hit the same area with a succession of droughts, cold snaps, floods, heat waves and wildfires that follow each other up rapidly. Within just one decade, the combined impact of extreme weather, falls in soil quality and air quality, habitat loss and shortages of food, water, shelter and just about all the basic things needed to sustain life can threaten most, if not all life on Earth with extinction.
|From the October 17, 2016, post 'Pursuing efforts?'|
A Global Temperature Rise Of More than Ten Degrees Celsius By 2026?
How much have temperatures risen and how much additional warming could eventuate over the next decade? The image on the right shows a potential global temperature rise by 2026 from pre-industrial levels. This rise contains a number of elements, as discussed below from the top down.
The magenta element at the top reflects the temperature rise since 1900. In February 2016, it was 1.62°C warmer compared to the year 1900, so that's a rise that has already manifested itself.
Rise from pre-industrial levels to 1900 (0.3°C)
Additional warming was caused by humans before 1900.
Accordingly, the next (light blue) element from the top down uses 0.3°C warming to reflect anthropogenic warming from pre-industrial levels to the year 1900.
When also taking this warming into account, it was 1.92°C (3.46°F) warmer in February 2016 than in pre-industrial times, as is also illustrated on the image below.
Warming from the other elements (described below) comes on top of the warming that was already achieved in February 2016.
Rise due to carbon dioxide from 2016 to 2026 (0.5°C)
The purple element reflects warming due to the amount of carbon dioxide in the atmosphere by 2026. While the IEA reported that energy-related carbon dioxide emissions had not risen over the past few years, carbon dioxide levels in the atmosphere have continued to rise, due to feedbacks that are kicking in, such as wildfires and reduced carbon sinks. Furthermore, maximum warming occurs about one decade after a carbon dioxide emission, so the full warming wrath of the carbon dioxide emissions over the past ten years is still to come. In conclusion, an extra 0.5°C warming by 2026 seems possible as long as carbon dioxide levels in the atmosphere and oceans remain high and as temperatures keep rising.
Falling away of the aerosols masking effect (2.5°C)
With dramatic cuts in emissions, there will also be a dramatic fall in aerosols that currently mask the full warming of greenhouse gases. From 1850 to 2010, anthropogenic aerosols brought about a decrease of ∼2.53 K, says a recent paper. While on the one hand not all of the aerosols masking effect may be removed over the next few years, there now are a lot more aerosols than in 2010. A 2.5°C warming due to removal of part of the aerosols masking effect therefore seems well possible by the year 2026, especially when considering further aerosol impact such as caused by burning of biomass, as discussed in this post.
Albedo changes in the Arctic (1.6°C)
Warming due to Arctic snow and ice decline (i.e. of both sea ice and the snow and ice cover on land) may well exceed 2.6 W/m², calculated Professor Peter Wadhams in 2012. This could more than double the current net global warming caused by people since pre-industrial times. Associated changes include the loss of the ice buffer (latent heat), greater heat transfer into the Arctic Ocean due to stronger winds (and the resulting freshwater lid on the North Atlantic) and more heat entering the atmosphere due to more open water in the Arctic Ocean. A 1.6°C warming due to albedo changes and associated changes seems possible over the next few years, as discussed in this post.
Methane eruptions from the seafloor (1.1°C)
|(view more images at the methane page)|
This 1.3°C warming (by 2100) from an extra 50 Gt of methane seems conservative when considering that there now is only some 5 Gt of methane in the atmosphere, and over the next ten years this 5 Gt is already responsible for more warming than all the carbon dioxide emitted by people since the start of the industrial revolution.
Professor Peter Wadhams co-authored a study that calculated that methane release from the seafloor of the Arctic Ocean could yield 0.6°C warming of the planet in 5 years (see video at earlier post).
In conclusion, as temperatures keep rising, a 1.1°C warming due to methane releases from clathrates at the seafloor of the world's oceans seems well possible over the next few years and even more warming seems possible beyond that, as also discussed in this post.
Rising temperatures will result in more water vapor in the atmosphere (7% more water vapor for every 1°C warming), further amplifying warming, since water vapor is a potent greenhouse gas. Extra water vapor will result from warming due to the above-mentioned albedo changes in the Arctic and methane releases from the seafloor that could strike within years and could result in huge warming in addition to the warming that is already there now. As the IPCC says: "Water vapour feedback acting alone approximately doubles the warming from what it would be for fixed water vapour. Furthermore, water vapour feedback acts to amplify other feedbacks in models, such as cloud feedback and ice albedo feedback. If cloud feedback is strongly positive, the water vapour feedback can lead to 3.5 times as much warming as would be the case if water vapour concentration were held fixed", according to the IPCC. The temperature rise due to extra water vapor works immediately, i.e. it goes hand in hand with rises due to other warming elements. Given a possible additional warming of 2.7°C due to just two elements, i.e. Arctic albedo changes and seafloor methane, an additional warming over the next few years of 2.1°C due to extra water vapor in the atmosphere therefore does seem well possible over the next few years.
Further feedbacks will result from interactions between the above elements.
- Changes to the atmosphere (clouds, storms, lightning, etc.)
Additional water vapor in the atmosphere and extra energy trapped in the atmosphere will result in more intense storms and precipitation, flooding and lightning. Flooding can cause rapid decomposition of vegetation, resulting in strong methane releases. Furthermore, plumes above the anvils of severe storms can bring water vapor up into the stratosphere, contributing to the formation of cirrus clouds that trap a lot of heat that would otherwise be radiated away, from Earth into space. The number of lightning strikes can be expected to increase by about 12% for every 1°C of rise in global average air temperature. At 3-8 miles height, during the summer months, lightning activity increases NOx by as much as 90% and ozone by more than 30%. The combination of higher temperatures and more lightning will also cause more wildfires, resulting in additional emissions such as of carbon dioxide, methane and carbon monoxide. Ozone acts as a direct greenhouse gas, while carbon monoxide can indirectly cause warming by extending the lifetime of methane.
- Changes to soils and ecosystems on land
Additional warming of the atmosphere can also result when sinks that are currently holding back warming, instead turn into sources. An increase in the uptake of carbon by vegetation until now was attributed in a recent study to higher CO₂ levels in the atmosphere. This land sink now appears to turn into a source of carbon emissions, due to deforestation and soil degradation caused by agricultural practices and more extreme weather, as discussed in this post.
- Changes to the cryosphere (global sea ice, snow and ice cover on land, glaciers, etc).
|From: Sea ice is shrinking|
To put this 2.615 million km² in perspective, the minimum Arctic sea ice in 2012 was 3.387 million km², 4.157 less than the minimum extent in 1980, as illustrated by the image on the right.
Ever warmer oceans and stronger winds that move sea ice away from Antarctica make the outlook for global sea ice grim. Furthermore, higher temperatures look set to cause more growth of algae and melting, resulting in further albedo decline. Higher temperatures on land will cause warmer water from rivers to enter the Arctic Ocean. Higher temperatures on land will also cause trigger more wildfires resulting in emissions such as of black carbon that can settle on the snow and ice cover in the Arctic.
A recently-published study warns that permafrost loss is likely to be 4 million km² (about 1.5 million mi²) for each 1°C (1.8°F) temperature rise. This is a self-reinforcing feedback loop, since the albedo loss will further speed up warming in the Arctic, which will also cause more emissions of carbon dioxide, nitrous oxide and methane.
[ image from: 10°C or 18°F warmer by 2021? ]
- Changes to oceans
Warmer water tends to form a layer at the surface that does not mix well with the water underneath, as discussed here. Stratification reduces the capability of oceans to take up heat from the atmosphere, thus speeding up warming of the atmosphere.
Until now, oceans have been taking up 93.4% of the extra heat caused by emissions by people. So, even a small decrease in the amount of heat that oceans take out of the atmosphere would result in a strong rise of global air temperatures.
Additionally, greater stratification of oceans results in less phytoplankton and thus less carbon dioxide that will be taken by oceans out of the atmosphere, so more carbon dioxide remains in the atmosphere. More carbon dioxide in the atmosphere means that less heat can leave Earth, as it gets trapped by the carbon dioxide, so this is another self-reinforcing feedback loop that further warms oceans, as described under feedback 29. Furthermore, ocean stratification can cause oceans to take up less heat from the atmosphere, resulting in more heat staying in atmosphere, while lower oxygen levels at sea surface can also increase releases of nitrous oxide.
In conclusion, the joint impact from further feedbacks may well amount to an additional 0.3°C warming over the next few years, or much more than that over more years, cancelling out possible over-estimations in other elements.
Summary: Total global temperature rise could be as much as 10°C or 18°F by 2021
In summary, adding up all the warming associated with the above elements results in a total potential global temperature rise (land and ocean) of more than 10°C or 18°F in a matter of years, by as early as 2021, assuming that no geoengineering will take place over the next few years.
|Abrupt Warming - How Much And How Fast?|
|[ click on images to enlarge ]|
Further reading on specific warming elements
• How much warming have humans caused?
• How much warming did and could people cause?
CO₂ 2016 - 2026
• Monthly CO₂ not under 400 ppm in 2016
• Accelerating growth in CO₂ levels in the atmosphere
• How much warming have humans caused?
Arctic sea ice and associated feedbacks
• Albedo Change in Arctic
• Storms over Arctic Ocean
• Sea ice is shrinking
• Accelerated Warming of the Arctic Ocean
• Arctic Sea Ice Getting Terribly Thin
• Arctic Sea Ice May Well Be Gone By September 2017
• Warning of mass extinction of species, including humans, within one decade
• Seafloor Methane
• The Methane Threat
• Temperature Rise
• It could be unbearably hot in many places within a few years time
• Extreme weather is upon us
• Abrupt Warming - How Much And How Fast?
Groups to discuss things further
• Electric Transport
• Climate Alert
• Climate Plan
• Extinction (this page)