How will permafrost affect and be affected by global environmental change?

Permafrost is defined as ground that remains at or below 0°C for at least two consecutive years. Permafrost underlies approximately 25 % of the land area in the northern hemisphere and can be up to 1500 m thick. Under current climate-change scenarios, permafrost degrades from both the top and bottom, increasing the depth of the “active layer”, and the extent of talik formation.

The deepening of the active layer could trigger the massive decomposition of organic matter stored in the first three meters below surface. The most recent estimates put the organic carbon pool in permafrost at 50% of the global soil organic carbon pool. This pool is equivalent to twice the amount of carbon in the atmosphere. The decomposition processes would lead to the emission of vast quantities of greenhouse gases, including methane and carbon dioxide, which could greatly affect the global climate.

Under the sea, permafrost occurs as subsea permafrost. Its presence on Arctic shelves is intrinsically linked to the occurrence of gas hydrates which are released to the atmosphere through “holes” in the permafrost, called gas seeps. Its exact distribution on the shelves of the Arctic has not yet been correctly assessed, which hampers the attempts to correctly depict the mechanisms of gas hydrate occurrence and release.

In alpine areas, permafrost is responsible for the occurrence and the preservation of landforms that could evolve dramatically, resulting in large scale natural hazards for alpine valley settlements. In the Arctic, rapid coastal erosion of permafrost is expected to increase dramatically following the drastic reduction of summer sea ice extent, threatening the existence of Inuit communities.

Permafrost observation and monitoring is probably one of the most important challenges of the twenty-first century

More information on theIPA website

What is the exact sensitivity of the climate system to changing greenhouse gas, dust and aerosol loading in the atmosphere?

The IPCC AR4 has shown that, although we understand better and better how the climate system works, there are still considerable uncertainties in evaluating its future evolution. Not only due to uncertainties in human emissions, but also because of flaws in our physical and biogeochemical understanding of the system. The unpredicted recent evolution of Arctic sea ice or of the Greenland ice sheet are magnificent examples of such flaws.

Although everyone legitimally wants to understand the impacts of climate change (which drives many other global changes such as water resources, biodiversity, agriculture, extreme events, etc…), or wants to develop strategies of mitigation and adaptation to global change, there is little hope in doing a good job in the two latter aspects of global change if one does not improve our physical understanding of the system.

Climate sensitivity is the clear prerequisite to all other physical aspects such as tipping points, feedbacks, thresholds, etc… Solving this question allows one to basically improve the response to all other questions, from the physics to the mitigation, going through the impacts.

What is the potential level of positive feedback that may come with the release of methane in the permafrost regions and continental shelves?

Given the potency of methane as a greenhouse gas, and also given the tremendous amount of methane stored both in the permafrost regions as well as the continental shelves, critical research needs to be done as to the level of positive feedback that may occur as some of this methane being released.

Massive releases of methane in earth’s past have played a pivotal role in dictating the direction and degree of climate change. While much attention has been given to carbon dioxide releases and sequestration, only a few scientists are currently studying methane releases going on in the thawing permafrost regions. Much more research needs to be conducted. The obstacles to doing this will be to move the focus of the press and policy makers from primarily carbon dioxide, to methane, as it is far more potent a greenhouse gas, and much more prone to significant positive feedback loops.

What is the net effect of changing cloudiness on global climate?

The net effect of the present cloudiness is to clearly cool the global climate. Will the green house gas induced climate change strengthen or diminish the net effect of clouds on, e.g. surface temperature?

How much and how quickly will methane be released from the polar regions?

There is more carbon locked up in methane (permafrost and clathrates) than carbon left on the planet in oil and gas. Methane is ~25 time more effective as a greenhouse gas so could have a massive impact on climate change. However we have little/no idea the rate of release of it either from the marine or the terrestrial envirment. Research is critically required now to understand the processed and then quantify the likely effects.

How is interdecadal-to-centennial natural variability taken into account in the IPCC GCMs projections?

This low-frequency natural variability might hide or intensify the climate system response to increased greenhouse gases in the atmosphere. In fact, for the next 30 years it seems that interdecadal natural variability would play a major role in the expected changes of rainfall and temperature in many regions, for instance, in South America.

How do the dual effects of greenhouse gases on the ocean (warming and acidification) interact with local stressors (overfishing and pollution) to reduce ecosystem services and cause extinctions?

The ocean covers 70% of the planet, yet the dual impacts of greenhouse gases are typically ignored – e.g. solutions designed to reduce heating without reducing CO2 concentrations ignore the threat posed by acidification. Moreover, we know little about the synergies between local and global stressors, and how reducing the former might buy us time to deal with the latter.

How to generate process of photosynthesis with out trees?

The natural process by which green house gases are removed from the atmosphere is the photosynthesis. But due to rapid deforestation and increasing green house gases (CO2) there could be shortage of oxygen in future. Atmospheric percentage of oxygen is only 21%, still sufficient, due to oxygen cycle. The process of photosynthesis requires CO2, water and a tree. But while percentage of trees going down and down per density of population shortage of oxygen likely. Then how to carry out process of photosynthesis without trees. Is there any method or can it be developed in future?

Climate change is expected to involve increasing climate variability. Can we manage our water resources while floods and droughts increase in frequency and severity without adding more storage space through building dams and other storage facilities?

Dams, surface, but also underground storage reservoirs are conventional means to reduce the dependability on the natural occurrence and availability of water. While these technical solutions are not without controversy storage facilities equipped with hydropower stations could even account for some GHG reduction. There is a need for an ideology free global assessment and recommendations for those regions where climate change is expected to manifest itself most viciously.

What happened in the interglacial/glacial transitions during the Pleistocene?

Since we are most likely entering a new ice age pulse soon it is essential to know the climate development of previous interglacials. Has Mankind prevented a new ice age pulse by enhancing the Greenhouse effect?