So long, farewell, auf weidershen, goodnight.

CONCLUSIONS: HOW HAS THE BLOG CHALLENGED MY PRECONCEPTIONS? 

At the start of this blog I had assumed that the response of glaciers to global warming was relatively conclusive. Numerous occasions of trying to preserve snowmen in the past have demonstrated, alongside the discourse of physics, that if atmospheric and surface temperatures increase than the snow will melt. However, this blog has indicated that this childhood assumption was overly simplistic.

I had assumed that alterations to glacial systems were mainly due changes in precipitation and temperature due to increasing greenhouse gas (GHG) emissions. However, over the course of several weeks I uncovered numerous regional forcings such as ABC and surface darkening by black carbon resulting in spatial and temporal variability in the response of glaciers to climate change. Scherler et al., (2011) article on the greater resilience of debris covered glaciers and Hewitt et al., (2005; 2011) research in the Karakoram region in particular underlined the importance of understanding local processes and feedbacks in order to predict glacial changes. Feedbacks at a continuum of scales cause non-linear responses to climate change, complicated by the presence of thresholds causing the reversal of some of these relationships apparent in the winter snow-monsoon interaction (Kripalini, et al., 2003).

This exercise has challenged the way I address articles on environmental change, and has emphasised the importance of reviewing several articles in order to obtain a clearer consensus of change within the glacial system. Each study has notable limitations and assumptions based on the method used to obtain and analyse their results. However by evaluating several studies the weaknesses of each individual method can be reduced. It is clear that substantially more research is required but current patterns suggest that the majority of glaciers in the region are in retreat. Although the IPCC (2007) statement may have been an exaggeration, this blog has shown that overall the claim that glaciers could disappear in the future, even if some time after 2035, is not.

Attempting to reduce anthropogenic climate change may be one of the greatest challenges that humans have to face in the next few decades. However, delaying this process will only increase the likelihood that an ireversible threshold is crossed. While current global temperatures are lower than past interglacials, predictions suggest this could change within the next few decades. Ultimately the future of the earth's systems is in our hands and how we act now will have significant implications for generations to come.

Conclusions: Major findings

Over the past three months this blog has reviewed some of the current literature on Himalayan glaciers in an attempt to understand how they are projected to respond to climate change. Drawing upon research using a variety of methods from proxy records to modelling some general trends are apparent.

The overall consensus within the literature is that substantially more research is needed (ICIMOD, 2011). Although the Himalayan region contains the greatest volume of ice and snow outside of the polar region (Kulkarni 1991), research has mainly been conducted on accessible glaciers generally in lower altitude regions. Of the 54,000 glaciers distributed within the Himalayan region, a comprehensive report by the ICIMOD (2011) in the Hindu-Kush Himalaya suggested that long-term field-based monitoring of glacial mass changes had only occurred on around a dozen glaciers. While remote sensing is increasingly being used to substitute for the lack of data, these images still require ground-truthing for validation. Therefore, although some general trends are apparent, significantly more research is required underlined by the complex spatial variability across the region.

MAJOR FINDINGS

Paleoclimatic records of past wamer interglacials periods including the Eemian (MIS 5e) and the Holsteinian (MIS 11) suggest that the current average global temperature is not unprecedented on a geological timescale (Hanson and Sato, 2011). Proxy records have indicated glacier extent in the Himalayas have also varied in the past responding to natural forcings from solar radiation and volcanic activity. However, it is not the level of warming that is the main concern but the rate of warming during the twentieth century. Crowley (2000) claims only 25% of the twentieth century warming could be accounted for by natural variability, with anthropogenic factors forcing climate  variability. This is a major concern in predicting future climate change as some anthropogenic inputs into the Earths systems such as black carbon are the product of human activity and therefore are absent from the historical record. Therefore understanding the direct and indirect effects are restricted to limited short-term instrumental studies resulting in high uncertainty in predictions of future climate change and its impacts on the glacial system.

Concurring with the overall trend around the world, glaciers in the Himalayas have generally been in a state of decline since the beginning of the twentieth century (IPCC, 2007). Some studies have also suggested that the rate of retreat in the Himalayas is two to eight times greater than the global average (Shrestha et al., 1999) attributed, in part, to additional regional forcing including atmospheric brown clouds (ABCs), surface darkening by black carbon (BC) and changes to the Asian monsoon (Li et al., 2011). These regional forcings result cause notable signatures in the response of Himalayan glaciers to climate change, adding to the spatial complexity across the mountain chain.

Overall, glaciers in the Himalayan region have been in a state of retreat since the beginning of the twentieth century. In addition to global rises in temperatures, regional forcing have resulted in complex spatial variability in the rate of retreat of glaciers across the region with greater declines in glacial extent reported in the monsoon-dominated southern and eastern Himalayan regions (ICIMOD, 2011). However, it is widely acknowledge that this general trend cannot be applied to all glaciers within the Himalayas. Research by Hewitt (2005; 2011) and Scherler (2011) have illustrated that glaciers in the Karakoram region are mainly static or advancing in some areas. This underlines the complexity of the atmospheric-land interactions feedbacks within the region, resulting in highly individualistic responses to climate change depending on current glacial extent and thickness, the presence or absence of debris, elevation and the dependence on the glacier on monsoon as a source of precipitation.

IMPACTS ON HIMALAYAN COMMUNITIES

Supplying 1.3 billion people with freshwater, the Himalayas are frequently referred to as the ‘Water Towers of Asia’ (ICIMOD, 2011). The lack of data and spatial complexity in the region make attempts to predict and mitigate against climate change particularly difficult as general trends cannot be applied across the region. Changes to glaciers within the Himalayas are likely to have numerous direct and indirect impacts on the communities that occupy the mountain region and surrounding lowland areas, occurring on a continuum of spatial and temporal scales. In the short term, increased glacial melt in projected to increase the frequency and magnitude of glacial lake outburst floods (GLOFs) and, assuming negligible changes in precipitation increase river discharge in glaciated river basins. However, shifts in the hydrological regime indicate that the buffering effect of the glacial component augmenting periods of low flow during years of failed or weakened monsoons may be reduced (Thayyen and Gergan, 2010). In the long term, under the business-as-usual scenario the discharge of rivers such as the Ganges with their headwaters in Himalayas are projected to decrease increasing water scarcity in the region (Rees and Collins, 2006).

CONCLUSIONS

Viewed within a context of increased development and growing population in the region, understanding the response of glaciers to climate change is essential in order to effectively manage against increased hazards and reduce water stress within the region. Climate change is likely to cause substantial changes to glaciers within the Himalayan region and worldwide. Although the IPCC (2007) projection may have been an overexaggeration it is widely acknowledged that under the the business-as-usual scenario most Himalayan glaciers are likely to disappear within the 21st century. Unless stricter measures are put in place, irreversible changes could result with severe socio-economic consequences. Alterations to the extent of these ice giants could have significant impacts on ecosystems, human society and most significantly, the dynamics the Earths system, and therefore maintaining glaciers is fundamentally important if we are to maintian the world as we know it.

Reference
Crowley, T. J. (2000) 'Causes of climate change over the past 1000 years', Science, 289: 270-277.

Hanson, J. E. and M. Sato (2011) Paleoclimate Data for Human-made Climate Change, NASA Goddard Institute for Space Studies: New York, 1-32.

Hewitt, K (2005) ‘The Karakoram anomaly? Glacier expansion and the ‘Elevation effect,’ Karakoram Himalaya.’ Mountain Research and Development 25,4,: 332-340

Hewitt, K. (2011) 'Glacier change, concentration, and elevation effects in the Karakoram Himalaya, upper Indus Basin', Mountain Research and Development , 31: 188-200

IPCC (2007) Climate Change 2007: Impacts, Adaptation and Vulnerability, in M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson (Eds) Contributions of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press: Cambridge.

Kulkami, A. V (1991) ‘Glacier inventory in Himachal Pradesh using satellite data.’ Journal of Indian Society of Remote Sensing,19,3: 195-203 

Li, Z., Y. He, W. An, L. Song, W. Zhang, N. Catto, Y. Wang, S. Wang, H. Lui, W. Cao, W. H. Theakstone, S. Wang and J. Du (2011) ‘Climate change and glacier changes in southwestern China during the past several decades’, Environmental Research, 6,4: 1-25.

Scherler,D; Bookhagen, B; Strecker,MR (2011) Spatially variable response of Himalayan glaciers to climate change affected by debris cover. Nat. Geosci. 4:156-159,doi:10.1038/NGEO1068, 2572,2583

Shrestha, A. B., C. P. Wake, P.A. Mayewski and J.E. Dibb (1999) ‘Maximum temperature trends in the Himalaya and its vicinity: An analysis based on temperature records from Nepal for the period 1971-94.’ Journal of Climate, 12: 2775-2767

Thayyen, R. J., and J. T. Gergan (2010) ‘Role of glaciers in watershed hydrology: a preliminary study of a “Himalayan catchment”, The Cryosphere, 4: 115-128.

The end is nigh: Conclusions- a different approach

As stated at the beginning of this blog, videos and pictures often speak louder than words. Therefore, in addition to a written post of the main conclusions of this blog and how it has challenged my preconceptions of the impacts of climate change on glaciers in the Himalayas, here is a video of a brief overview of some of my findings.

ICIMOD: Climate change and its impacts on the cryosphere and water resources of Hindu Kush Himalaya

Over the last three months this blog has attempted to review some of the current literature on climate change and its impacts on glaciers within the Himalayan region. The regional variability demonstrated from research in the Hindu Kush-Himalaya underlines the complexity of glaciers response to climate change. However, some general patterns are apparent. This video by Shretha (2008) a Climate Change Specialist at the ICIMOD covers most of the topics discussed in my blog and provides a good overview of the state of glaciers in the the Himalayan region.

The video is relatively long, but is highly informative drawing upon paleoclimatic records and instrumental records to provide a comprehensive summary of the current state of glaciers in the Himalayas. Although fieldwork research is unevenly distributed, and is clustered mainly in Nepal and lower altitude regions, by combining different proxies to assess changes increases the validity of the observations that have been drawn.

Breakdown on video:
0-8 minutes: Introduction to HKH and patterns of changes to glaciers in the region due to climate change
8+ minutes: Impacts of these changes on local communities including GLOFs and changes to river discharge

In the news this week...

THAWING PERMAFROST DECREASES RUNOFF TO THE RIVER YANGTZE

Researches at the Chinese Academy of Sciences (CAS) have observed a 15% decrease in runoff entering the river Yangtze over the last four decades despite increases in glacial melt and precipitation (Qui, 2012). This contrasts from other rivers surveyed in western China such as Tarim river which showed a 13% increase in input into the river coinciding with a 26% increase in glacial melt since 1961.

The decrease in the input to the Yangtze river was attributed to changes in permafrost on the Tibetan Plateau, the source of the Yangtze headwaters. The causes for this feedback are still uncertain however, Wang et al., (2012) suggest either the increase in the active ground layer  at some sites has reduced surface runoff as more water is infiltrating into the upper surface layer or more water may be percolating through the the surface as groundwater. Dependent on air temperature and vegetation cover, degradation of wetland habitats on the plateau is also contributing to reduced runoff causing a different discharge pattern to other regions of China and general patterns worldwide (Qui, 2012). 

This article highlights the importance that permafrost can have in altering the response of river discharge to glacial melt. Ge (2012 cited in Qui, 2012) states that permafrost contributes up to a quarter of the earth's surface and could be 'just as important [as glaciers] in terms of water resources, especially in places such as the Tibetan Plateau'. The findings from this article underline the complexity of predicting changes to water resources in the Himalayas and the importance of further basin-level research that accounts for all of the processes affecting river discharge.

STUDY COMPARING RECENT WARMING AGAINST THE PALEOCLIMATIC RECORD

Using ice cores from the Arctice and Antarctica and deep ocean sediment cores, Hansen and Sato (2011) compared the current climate against two previous interglacials: Eemian and Holsteinian period (also known as Marine Isotope Stages 5e and II respectively). Despite some discrepencies between the ocean and ice cores, overall the proxy data suggests current global temperature is only 1°C lower than during the Eemian period. Therefore, Hanson and Sato (2011:17) argue that target set for maximum 2°C temperature rise is inadequate as it would exceed temperatures during the Eemian interglacial where sea-levels were approximately 4-6 metres higher than present, and would raise global temperatures closer to those observed for the Pliocene where sea level had been around 25 metres higher than current levels. Recognising that ice disintegration is a non-linear process Hanson and Sato (2011) suggest that for every 1°C rise in temperature, sea-level will rise by 20 metres suggesting an increase in sea level by several metres by 2100. Accepting some slow feedbacks to current global temperatures means further rises are highly likely, Hanson and Sato (2011) suggest carbon dioxide levels need to be reduced to 350ppmv (compared to present level of 390ppmv) to stabilise increases in global temperature to 1°C.

Using paleoclimatic data in research is essential in order to put current environmental changes into perspective. Findings from this paper suggest the 2°C limit set by government organisations may be inadequate, and Hanson and Sato (2011) claim this limit was set on what is politically realistic rather than on scientific research. A highly controversial statement this paper demonstrates that despite warmer periods occurring in the past, the current rate of temperature increase is unprecedented in the historical record.

Global temperature relative to the Holocene based on ocean proxy record where levels have been amplified by 1.5 to provide an estimate for surface values (Source Hanson and Sato, 2011: 20)

Reference:
Hanson, J. E. and M. Sato (2011) Paleoclimate Data for Human-made Climate Change, NASA Goddard Institute for Space Studies: New York, 1-32.

Qui, J. (2012) 'Thawing permafrost reduces runoff', Nature, 9749.

New Year Resolutions: A fresh start for climate change?

Source: Lebel, A. T (2011)

A new year, and yet another long list of resolutions for us all to try and in my case fail to stick to. So instead, I have decided to set myself targets. Must be the academic ' I must try harder' system getting to me but a review of the recent media regarding climate change suggests that the public as a whole are becoming  blasé with regard to tackling climate change. The annual release of the British Social Attitudes survey last month suggested that public support for climate change had fallen dramatically from 50% concerned that climate change is not high enough on the political agenda a decade ago to 34% today. (Guardian, 5th January, 2012)

But how can this be possible? Comprehensive reports such as those of the IPCC and an overwhelming majority of the scientific literature suggest that climate change is occurring. Some such as Crutzen (2002) state that we have entered a new epoch, called the 'Anthropocene' due to the significant changes that human activity has caused to the environment. However, as it made apparent in the Durban conference in November, governments are still reluctant to act stating more research is provided. Aside from the political and economic factors embedded within the conference, current reluctance can be partially attributed to anti-science. The requirement for media to provide neutral coverage of a story mean uncertainities in models and gaps in data are being equally disseminated to the public. The complexity of the earth's system means that models can never completely remove uncertainity from projections on future climate change and therefore if government's wait until models are certain of their predictions attempts to mitigate against climate change will already be too late.

Clear examples of this anti-science have been highlighted by Peter Gleick (2012) in his release of the second 'Bad Science of the Year Awards' for 2011.

So from this, I have decided if there's one thing that I can do this year is try to increase other people's awareness on climate change and show them how it's not an inevitable outcome of economic development. The Guardian (5th Janurary 2012) argue that many people have heard of climate change but through exaggerated headline grabbing articles or on neutrally weighted documentaries. 

 Many people claim that one person can't make a difference but then if you can convince one person and them another it may just start a chain reaction. Therefore, new year, new start, new target, 2012 could be the year to make real progress on reducing climate change.

Reference:
Cruzen, P.J. (2002) 'Geology of mankind', Nature, 415,1: 23

The Guardian, (2012) 'The climate change message is not being heard. Here's how to change tack', The Guardian, 5th January 2012, (www) http://www.guardian.co.uk/commentisfree/2012/jan/05/climate-change-message?newsfeed=true (Accessed 5/01/12)

Up the creek without a paddle: Impacts and Adaptation Prospects for Himalayan Communities

A review of the current literature on changes to Himalayan river discharge due to glacier retreat  indicates that in the short term discharge will increase, followed by a decrease when the glacial component begins to fall. Rivers sourced from the Himalayas, flow into seven countries and support one-third of the world’s population, although this proportion is growing. Therefore, understanding the impacts and potential mitigation strategies available is highly relevant for both policy-makers and scientists and is the focus of this post.

THE CURRENT STATE OF RIVER DISCHARGE

Hasnain (2002) and Xu et al., (2009) suggest that the glacial component can contribute between 70 and 80% of the summer flow of Himalayan rivers during the 'shoulder' season (before and after precipitation from the summer monsoon). Augmenting against  years of low flow due to absence or weakening of the monsoon the glacial component acts a buffer maintaining flow during the summer period when demand for freshwater is highest. It is widely acknowledged that (excluding the Karakoram region) the glaciers in the Himalayas are receding at a greater rate than the world average (Xu et al., 2009). However, the current state of the Himalaya's rivers is largely uncertain. To assess the impact of glacier retreat on Himalayan communities in the next fifty years it is important to place the current discharge levels into the projected bell-shape curve model of discharge predicted by Rees and Collins (2006: 2166)

Hasnain (2002) conducted a six-year study of the Dokraini glacier at the headwaters of the River Ganges in India. Between 1994 and 2000, the total discharge of the river increased from 243 x 10⁵m³ to 1915 x 10⁵m³, of which the glacial component consisted between 82 to 91% (Table 1) It should be noted that no observations were taken in 1998, and that the stated component contributions in 1994 do not add up to the total measured discharge. However, even if the 1994 values are excluded from the analysis discharge in 2000 is over seven times greater than in 1995 suggesting an increase in discharge in the region.

 This rise in discharge is supported by a later study by Hasnain (2008) reviewing the current literature on Himalayan river discharge in the eastern and western Himalayas. General observations from the studies suggest an overall increase in discharge by 3 to 4% due to a 10% and 30% increase in glacial melt in the western and eastern Himalayas respectively. However, Hasnain (2008) argues that attempts to predict future changes in river discharge are limited by the lack of long-term studies in the region. Although remote sensing is now being used to substitute fieldwork data, ground truthing is still required to calibrate and validate the images. However, the current studies available indicate that discharge has already started to rise supported by Rees and Collins (2006) model of hypothesised western and eastern catchments.

ADAPTING TO CHANGING RIVER DISCHARGE

Moors et al., (2011) claim that even if there was no significant change in total water availability by 2050, seasonal changes in the timing of glacial melt and increased variability in the summer monsoon will exacerbate water stress across the Himalayan region. Observed rises in regional temperature alter the timing of the glacial component runoff relative to the monsoon. Removal of this buffer against low flow, is a significant concern for policy makers as it coincides with the period of greatest demand on water resources for domestic and agricultural use (Xu et al., 2009).

Therefore mitigation methods against a projected long-term decrease in river discharge and the hydrological regime are an increasing priority for countries that depend on the Himalayan rivers. Because many rivers cross between countries, trans-boundary organistations such as the International Centre for Integrated Mountain Development (ICIMOD) having been formed. Serving eight regional countries within the Himalayan region, the ICIMOD have been actively promoting water harvesting and increased water efficiency with the former now occurring in five of the eight countries(Chalise, 2002). However, this project is still limited in scale and Xu et al., (2009) argue that rather than disjointed policy approaches, a scale of adaptation needs to be adopted related to uncertainty. Occurring at different scales, Xu et al., (2009) support a pragmatic approach to mitigation, including the local people and recognising the different requirements of urban and rural communities. Essential to successful mitigation against water scarcity is the development of schemes at a river-basin level, focusing on decreasing water demand, modernising irrigation and acknowledging the demands of communities downstream for high quality water (Xu et al., 2009; Moors et al., 2011). Through a pragmatic approach, long-term priorities can be identified and cooperation between countries can minimise conflict due to water scarcity. Numerous examples of trans-boundary conferences such as the Climate Summit of the Himalayas suggest movements towards an international agreement. However, the current state of progress is limited due to substantial gaps in our understanding of basin-specific responses to climate change and uncertainties of future economic and social demands (ICIMOD, 4th December 2011).

CONCLUSIONS

Overall, the significant contribution of the glacier component to river discharge coupled with the rapid retreat (excluding Karakoram) of glaciers in the Himalayas relative to the world average suggests future climate change could have substantial impacts on the 1.3 billion people that rely on Himalayas rivers. Causing both long-term and seasonal changes to river discharge, attempts to reduce vulnerability to water stress will require trans-boundary cooperation managing water resources at a basin scale. According to Rees and Collins (2006) bell-curve, in the short-term discharge may increase in these basins, however countries should utilise this short-term opportunity, improving water efficiency, decreasing demand and researching alternative water sources where possible. Under the business-as-usual scenario, in the long-term river discharge will decrease, and with growing populations and increased demand a robust international agreement on water use will be essential.

Reference:

Hasnain, S. I. (2002) ‘Himalayan glaciers meltdown: impact on south Asian rivers’, FRIEND Regional Hydrology: Bridging The Gap Between Research and Practice, Proceedings of the Fourth FRIEND Conference, South Africa, March 2002, 274: 417-425.

Hasnain, S. I (2008) ‘ Impact of climate change on Himalayan glaciers and lakes’, Proceedings of Taal2007: The 12^th World Lake Conference: 1088-1091.

ICIMOD (2011) 'The Status of Glaciers in the Hindu Kush-Himalayan Region' (www) http://www.icimod.org/?q=5934 (Accessed 4/01/11)

Moors, E. J., A. Groot, H. Biemans. C. T. van Scheltinga, C. Sidevius, M. Stoffel, C. Huggel, A. Wiltshire, C. Mathison, J. Ridley, D. Jacon, P. Kumar, S. Bhadwal, A. Gosain and D. N. Collins (2011) ‘Adaptation to changing water resources in the Ganges basin, northern India,Environmental Science and Policy, 14: 758-769.

Rees, H.G. and D. N. Collins (2006) ‘Regional differences in response of flow in glacier-fed Himalayan rivers to climatics warming’, Hydrological Processes, 20, 10: 2157-2169.

Xu, J., R. E. Grumbine, A. Shretha, M. Eriksson, X. Yang, Y. Wang and A. Wilkes (2009) 'The melting Himalayas: cascading effects of limate change on water, biodiversity and livelihoods', Conservation Biology, 23, 3: 520-529.