UK-Russia Climate Change Collaboration
UK-Russia Climate Change Collaboration
‘Climate impacts in Russia: changes in carbon storage and exchange’
The overall goal of the project ‘UK-Russia Climate Change Collaboration’, funded by the UK Foreign and Commonwealth Office, is ‘to improve the UK and Russia’s understanding of climate change science and climate change impacts (physical and economic) on Russia and the UK’. Over 3 years, this work aims to raise the profile of climate science through various outputs, including a joint research programme, and awareness raising activities, and as a result will provide a platform from which greater account can be taken of climate science evidence in policy-making.
The territory of the Russian Federation covers more than one eighth of the Earth’s land mass, extending over much of northern Europe and Asia. At these latitudes, climate warming due to human greenhouse gas (GHG) emissions is generally expected to be strongest (Intergovernmental Panel on Climate Change (IPCC), 2007). Changes in climate will bring about changes in the terrestrial ecosystem of this region, which ranges from tundra and taiga forests in the north to steppe grasslands and deserts in the south. Examples of these changes include a widespread thawing of the permafrost; a northward and upslope migration of the treeline; and a concurrent increase in forest degradation from the south, due to a mounting risk of desertification and natural disturbances such as wildfires, and a growing pressure for expansion of agriculture. Because of their effect on the energy, water and carbon balance over such a large land surface, many of these changes have the potential to feed back to the regional or global climate. The terrestrial ecosystem in Russia is therefore a key part of the global climate system and plays a significant, but still poorly understood, role in the global water and carbon budget.
Past trends in climate over Russia
The 20th century has seen distinct changes in temperature regime, seasonality and extremes over Russia that were generally stronger than the global mean. Between the years 1907 and 2006 the annual mean temperature rose by about 1.3 ° C, which is more than 1.5 times the global average warming of 0.7 ° C in the same period. This rise was particularly strong over the last decade or so (Meleshko, 2008). The annual mean temperature trend over the 20th century was smallest in North-Eastern Russia (1.1 ° C per century) and largest in West Siberia and the Baikal region (1.5 – 1.7 ° C per century). Also, warming was strongest in winter (1.7 ° C per century over all of Russia) and least in summer (0.6 ° C per century). The annual temperature minima over the past 30 years rose more than the annual maxima (on average 0.8 ° C vs 0.6 ° C per decade), with regional increases in the annual minimum temperatures of up to 2.6 ° C per decade (Meleshko, 2008) (see Figure 1).
Figure 1: Departures of the annual surface air temperature (°C) averaged over Russia from the baseline climatic norm (1961–1990). (Thin line: observed temperature; thick line: 11-year moving smoothing) (Meleshko, 2008).
Trends in precipitation are more difficult to discern because of the larger natural variability and a less homogenous and dense observation network. According to some studies, annual and seasonal precipitation totals for all of Russia have tended to decrease over the last 50 years, with the most pronounced decrease occurring in the northeastern part of the country. A weak tendency of precipitation to increase was observed over European Russia. Trends in snowfall and snow depths are similarly uncertain, but mostly show an increase, especially across north-central Eurasia.
These observations in Russia are consistent with what is seen globally and in other regions. They are in line with a general perception of a world shifting towards a warmer and wetter climate with more extreme precipitation events in some places and also more frequent and/or longer lasting droughts.
Future projections in climate
Most climate models are able to reproduce the observed trends in mean annual temperature over Russia, but tend to underestimate the actual temperatures as well as the inter-annual variability, and overestimate the precipitation trends in most regions. For the 21st century, the global climate models that participated in the IPCC’s 4th Assessment Report project an acceleration of the warming trend that was already observed in the past century (IPCC, 2007) (Figure 2).
Figure 2: Temperature anomalies with respect to 1901-1950 for the Northern Asia region (indicated by the green rectangle) for 1906–2005 (black line) and as simulated by MMD models incorporating known forcings (red envelope); and as projected for 2001–2100 by MMD models for the A1B scenario (orange envelope). The bars at the end of the orange envelope represent the range of projected changes for 2091-2100 for the B1 scenario (blue), the A1B scenario (orange) and the A2 scenario (red).
From the IPCC (2007, Figure 11.8).
Warming is projected to be higher in winter than in summer, and is likely to be greatest in the continental interior and at high latitudes in northern Russia. The models also indicate that a considerable increase in annual precipitation will occur in northern high latitudes at a much faster rate than the global mean. The precipitation changes projected for Arctic region have a pronounced seasonality, with the strongest relative increase in winter and fall, and the weakest in summer.
Results from the IPCC multi-model ensemble show a high degree of confidence in the direction of change in both annual temperature and precipitation by the end of the 21st century. All ensemble models show increasing temperatures and precipitation, with an ensemble median value of 4.3 ° C and 15%, respectively (IPCC, 2007). However, there is considerably less certainty in the direction of change in precipitation during the summer months. Most climate models project drier summer conditions over at least some regions of northern Eurasia, longer droughts, and a smaller number of wet days, but at the same time also they also predict an increase in heavy precipitation intensity. Future projections for precipitation extremes in this region are however prone to large uncertainties as climate model simulations of extreme events are less reliable.
Changes in permafrost
Thawing permafrost and the subsequent release of previously frozen organic carbon is one of the potential feedbacks from high-latitude regions to the global climate results (Schuur et al., 2008). Permafrost underlies more than 60% of the land in Russia and is generally thought to be highly sensitive to global warming. Many studies have projected the impacts of climate warming on permafrost during the 21st century using models of different complexity at range of geographical scales from local to pan-arctic. They consistently predict ground temperature rise, deepening of the uppermost layer of seasonal thawing (active layer), and reduction of area occupied by frozen ground in the near surface soil layer with relict permafrost remaining at larger depth for longer time.
In reality, the response of permafrost to climate warming is likely to be more complex than some simplified equilibrium model simulations have suggested. Changes in the permafrost extent and the active layer thickness are governed to a large degree by changes in snow cover and vegetation, and a key issue in the coming few decades will be the balance between the abundance of lower vegetation and mosses on the one hand, and an advancement of shrubs into the tundra on the other.
Large-scale permafrost degradation will allow previously frozen organic material to decompose, contributing to greenhouse gas fluxes to the atmosphere and enhancing global warming. In addition, geomorphological processes associated with thawing permafrost, such as thermokarst and erosion, can expose relatively deep deposits, allowing further decomposition (Schuur et al., 2008). A major source of uncertainty is the availability of the organic material in permafrost, as this ultimately governs the strength of potential feedback to global climate. Recent findings suggest that pan-arctic permafrost together with the active layer above it contain up to 1850 Gigatonnes (Gt) of carbon, including almost 300 Gt in the form of peat (McGuire et al. 2009; Tarnocai et al. 2009, Zimov et al., 2006;). This is twice as much as in the global atmosphere.
Carbon emissions from thawing permafrost can be in the form of carbon dioxide (CO2) or, if the decomposition takes place in anaerobic conditions, as methane (CH4). Production of methane is favoured in wetlands. Although boreal wetlands and peatlands are an important source of methane, they are a sink for atmospheric CO2. However, methane has a much stronger greenhouse effect than an equivalent amount of CO2, albeit with an average residence time in the atmosphere of only 12 years. Initial modelling suggests that by the middle of the 21st century methane emission from wetlands in Russian permafrost region may increase by 25%–30% (Anisimov & Reneva, 2006). The overall climate feedback of the additional annual source of methane in the order of 6-10 Mt appears to be relatively small (Anisimov 2007). It should be noted, however, that few studies have accounted for changes in the hydrological conditions. In peatlands, the balance between carbon uptake and decomposition ultimately depends on the depth of the water table. A lowering of the water table, whether due to permafrost degradation, changes in climate or human activities, will result in the exposure of previously submerged peat. This will lead to enhanced aerobic decomposition and CO2 emissions, but a reduction in methane production. Likewise, an increase in precipitation may raise the water level and expand the saturated area, resulting in a net increase in methane emissions. The net amount of CH4 emissions therefore depends on the interaction between both climatological and hydrological conditions.
Changes in natural ecosystems
Roughly half of territory of the Russian Federation is forested, and there is evidence that these boreal forest ecosystems have already started to respond to the transient effects of climate change in recent decades. Predicted impacts of climate change generally include a northwards and upslope movement of the treeline as well as a modification of the current forest composition, changes in productivity and moisture-related dieback in certain tree species under warmer conditions, and an increase in insect infestation and wildfire disturbance. All these changes have potential to provide feedback to the climate system because of their effect on the surface albedo , roughness and energy balance, and carbon and water fluxes. Some studies have predicted dramatic changes in land cover in Siberia by the end of the 21st century. These include an almost complete disappearance of tundra ecosystems, a northward migration of the taiga zone, and an expansion of steppe, semi-desert and desert areas at the expense of boreal forests. However, few of these studies account for the actual succession and migration rates of the northern treeline, and some authors have suggested it is unlikely that the anticipated northward expansion of the boreal forest will be finished by the end of this century. This also implies that the boreal forest may continue to respond to global warming decades after a stabilisation of the climate. This concept of ‘committed ecosystem change’ means that natural ecosystems such as tundra and boreal forests may be committed to substantial changes long before these are observable, and may therefore continue to respond for many decades following climate stabilisation (Jones et al., 2009).
The vegetation and soil of the Siberian forest ecosystems are considered to be significant stores of carbon. Boreal forests are furthermore thought to be a significant sink for atmospheric CO2. The size of this sink remains uncertain, but some authors have suggested the Russian boreal forest in its current state has only a limited capability to compensate for anthropogenic carbon emissions. There are even indications that northern high latitude areas (north of 50-N) as a whole may currently be a net source of carbon, when the effects of forest fires and methane emissions from wetlands are taken into account. However, there is substantial uncertainty in estimates of annual carbon emissions due to forest fires and their net climatic effect on a longer time scale remains unclear. Meteorological observations indicate a statistically significant increase in fire hazard over the 20th century for Siberia and the Russian Far East, but satellite data do not support a consistent increase in fire frequency in Siberia in recent years. For the 21st century, an increase in fire activity and extension of the fire season due to climate change is commonly anticipated, although some studies have found a reduction in fire frequency in certain regions, reflecting wetter conditions due to an increase in precipitation. It remains therefore uncertain whether the combined net effect of all these factors will push the high-latitude forest ecosystems towards being a sink or a source of CO2.
Changes in agricultural ecosystems
The majority of commercial agriculture in Russia is focused in the Southern European region. This area has high inter-annual climate variability with droughts occurring regularly. It is generally thought that warmer and wetter conditions during the coming decades coupled with increased atmospheric CO2 concentrations will be beneficial for agriculture in high latitudes. In Northern Europe, the suitability and productivity of crops is likely to increase and extend northwards. Due to a longer planting window and generally more favourable growing conditions, large gains in potential agricultural land in the Russian Federation have been predicted. However, several more specific studies predict that climate change will not drastically improve Russian agricultural output (Alcamo et al, 2007, Dronin & Kirilenko, 2008). Expansion of agriculture into the boreal forest region may in reality turn out to be difficult as the growing season is short and in many areas the soils are thin, acidic and unsuitable for agriculture. In the more productive, southern areas, the disadvantageous impacts of higher temperatures, such as lower harvestable yields, higher yield variability and reduction in suitable areas for traditional crops, may be predominant. This has significant implications in terms of country level food security. The negative impact of very high temperatures on agricultural productivity may be exacerbated by a change in the frequency of extreme weather events. Even if the changes in crop production are small on average, the projected increase in heat waves and droughts may double the risk of food production shortfalls in the main crop growing regions in the 2020s, and triple it in the 2070s (Alcamo et al., 2007).
Several studies have highlighted the potential for changes in agricultural management practices to reduce soil organic carbon losses in the future and thus mitigate future climate change. In a global analysis (Smith et al, 2007a, Smith et al, 2007b), the climate mitigation potential from agriculture in the Russian Federation was ranked 6th amongst the 22 world regions considered. However, climate change could also potentially influence the effectiveness of agricultural mitigation measures. A key factor will be the overall influence of changes in those factors that control the cycling of carbon and associated GHG fluxes. For soil carbon this will depend on the balance between how changes in precipitation (and temperature and CO2 concentration) alter crop and grassland productivity and hence carbon inputs to soil on the one hand, and how changes in soil moisture (and temperature) affect losses of soil carbon through decomposition on the other hand. Additionally, the scale and technique of land management, and the use of agricultural technology can have a marked impact on these factors.
The bulk of the scientific literature predicts major changes in the natural and agricultural ecosystems of Russia as a consequence of climate change. The response of the permafrost to climate warming is thought to play a key role in the global climate system because of the large amounts of carbon stored in frozen soils, particularly in the wetlands. Although initial modelling results do not provide evidence for a major feedback effect on the global climate, the extent and rate of permafrost thawing, and the associated carbon emissions to the atmosphere, are still very uncertain.
In the longer term, a warmer climate will promote tree and shrub growth, leading to an expansion of the boreal forest into the current tundra ecozone. However, the migration of the treeline may lag behind a change in climate by several decades, if not centuries. At the same time, there may be an increasing pressure on the forest from the south due to an increase in natural as well as human disturbances. Furthermore, a hotter and drier growing season which is more prone to droughts may adversely affect agricultural productivity in some of today’s main agricultural regions.
All these changes will affect the carbon dynamics of the territory of the Russian Federation. Тhere are considerable uncertainties in the current estimates of the carbon pools in the Russian soils and forests. Widespread thawing of the permafrost and a decrease in forest extent may contribute to a negative carbon balance. Сurrently, at circumpolar scale, Arctic vegetation and the active layer are unlikely to be a large source or sink of carbon in the form of CO2. They are, however, most likely a source of positive radiative forcing due to large methane emissions; even in tundra areas that are net sinks of carbon, significant emissions of methane lead to positive forcing (IPCC, 2007). Agriculture can play an important role in climate change mitigation mainly through reduced and avoided emissions and enhanced carbon storage, and studies suggest there is large potential for agricultural climate mitigation in Russia.
1. Alcamo, J., N. Dronin, M. Endejan, G. Golubev, and A. Kirilenko (2007): A new assessment of climate change impacts on food production shortfalls and water availability in Russia. Global Environ. Change, 17, 429–444, doi:10.1016/j.gloenvcha.2006.12.006.
2. Anisimov, O.A. (2007): Potential feedback of thawing permafrost to the global climate system through methane emission. Environ. Res. Lett., 2, 045016, doi:10.1088/1748-9326/2/4/045016.
3. Anisimov, O.A., and S.A. Reneva (2006): Permafrost and changing climate: the Russian perspective. Ambio, 35(4), 169-175.
4. Dronin, N., and A. Kirilenko (2008): Climate change and food stress in Russia: what if the market transforms as it did during the past century- Climatic Change, 86:123–150, doi:10.1007/s10584-007-9282-z.
5. IPCC (2007): Climate Change 2007: The Physical Science Basis. Cambridge: Cambridge University Press.
6. Jones, C., J. Lowe, S. Liddicoat, and R. Betts (2009): Committed terrestrial ecosystem changes due to climate change. Nature Geoscience, 2, 484–487, doi:10.1038/ngeo555.
7. McGuire, A.D., Anderson, L.G., Christensen, T.R., Dallimore, S.,Guo, L., Hayes, D.J., Heimann, M., Lorenson, T.D. , Macdonald, R.W., and Roulet, N. 2009. Sensitivity of the carbon cycle in the Arctic to climate change. Ecological Monographs 79 (4): 523-555.
8. Meleshko, V.P. (Ed.) (2008): Assessment Report on Climate Change and its Consequences in Russian Federation. Moscow: Roshydromet (in Russian).
9. Schuur, E.A.G., J. Bockheim, J.G. Canadell, E. Euskirchen, C.B. Field, S.V. Goryachkin, S. Hagemann, P. Kuhry, P.M. Lafleur, H. Lee, G. Mazhitova, F.E. Nelson, A. Rinke, V. E. Romanovsky, N. Shiklomanov, C. Tarnocai, S. Venevsky, J.G. Vogel, and S.A. Zimov (2008): Vulnerability of Permafrost Carbon to Climate Change: Implications for the Global Carbon Cycle. BioScience 58(8), 701-714, doi:10.1641/B580807.
For details of the research programme and literature review:
Dr. Oleg Anisimov
State Hydrological Institute
23, second Line V.O.
Tel: +7 812 323-35-17
Fax: +7 812 323-10-28
Dr. Rutger Dankers
Meteorological Office Hadley Centre
Tel: +44 (0)1392 886212
Fax: +44 (0)1392 885681
A group of parallel model simulations used for climate projections, used to obtain an estimate of uncertainty
The process by which characteristic landforms result from the thawing of ice-rich permafrost or the melting of massive ground ice
The fraction of solar radiation reflected by a surface or object, often expressed as a percentage