Gianni Tartari, Franco Salerno, Sudeep Thakuri,
Andrea Lami
LAKES AS INDICATOR OF CLIMATE CHANGE
IMPACT ON QUANTITY, QUALITY AND BIOLOGY
OF THE
2nd Third Pole Environment (TPE) Workshop
TPE’S WATER RESOURCES
1. What is known and unknown?
Climate research gaps
• The world has passed through a decade long Global warming stagnation period,
but the debate has started whether the warming is permanently paused or is
temporary which accelerate after some period (Kerr, 2009).
• The complex spatiotemporal Variability of Asian Monsoon system only recently
appear understood and is still difficult to predict the different patterns of
climate change (Temperature and Precipitation) across the TPE (Cook et al, 2010)
Water research gaps
• Lack of scientific data for analysing the Different Patterns of Climate Change
Impacts on Water Resources across the TPE is one of the major limitation.
Many of the current researches are focusing on some single components of the
water cycle, but with really few Linkages among them (reality is complex:
oversimplification, exaggeration, or ignoring serious matters can be
consequential, Kargel et al. , 2010).
• In many case the researches are confined to the Quantitative aspects of the
change, forgetting completely the impacts on Quality and Biology of water
bodies.
2nd Third Pole Environment (TPE) Workshop
2. Global and North Hemisphere warming
Temperature rise per decade (°C 10 y-1)
Global
North
since 1901
0.07
0.08
since1960
0.13
0.24
Absolute temperature rise (°C)
Global
North
since 1901
0.75
0.89
since1960
0.63
1.12
North Hemisphere warming is now 0.24 °C decade-1 since 1960, the double than
the Global warming (0.13 °C decade-1).
These studies show two phases of global warming (1910s- 1940s and 1960snow) separated by a period of stagnant temperatures (Kerr, 2009). The warming
from the 1910s to the 1940s is attributed to natural causes (Brönnimann, 2009).
By contrast, the warming since the 1960s is attributed largely to anthropogenic
influences .
Therefore we argue since 1960s.
2nd Third Pole Environment (TPE) Workshop
3. Glacier and Lakes changes across the region since 1960
•
•
•
•
Modified from Kargel et al. , 2010
Precipitation lees influenced by monsoon
Glaciers grow by winter accumulation
Less glacier disintegration (advances)
• Less intense melting, more
Lakes growth
intense sublimation
• Less debris cover
• More sensitive to precipitation
changes and wind
• More intense melting
• More debris cover
• Glaciers are more sensitive to
warming
• Precipitation more dominated by monsoon
• Glaciers grow by summer accumulation
• More lake growth and glacier disintegration
Glacier and lakes behavior varies across the region, with faster retreat in the east. Sensivity could be influenced by
Elevated Heat Pump (EHP)
2nd Third Pole Environment (TPE) Workshop
4. Our key questions
1)
how is the spatial pattern of the climate change across the TPE range?
2)
how is this pattern impacting the water quantity, water quality
and biology/ecology of glacial lakes.
2nd Third Pole Environment (TPE) Workshop
5. Aims of this presentation
Focus the attention on lentic
environments, considering
their clear dependency with
climate change and glacial
retreats.
To propose a
methodological approach to
use lakes as indicator of
change across the spatial
pattern of the TPE.
The CCQQB Project
2nd Third Pole Environment (TPE) Workshop
A methodological approach based on two decades of experience
This activity started in the 1989 by IRSA-CNR in the framework of the projects
carried out by the EvK2CNR Committee and in collaboration of NAST. Since
1994 the activity is developed jointly with ISE-CNR. More recently has been
included in the context of the interdisciplinary activities promoted by SHARE.
CCQQB is presented as core project on water resources in SHARE Program
(Stations at High Altitude for Research on the Environment)
2nd Third Pole Environment (TPE) Workshop
6. Our case study
Himalaya: Sector 4
The inventory of the Nepali
Lakes reveales 2323 glacial
lakes above 3,500m (Mool et al.
2001).
Potentially dangerous glacial lakes in Nepal.
(Mool et al. 2001)
2nd Third Pole Environment (TPE) Workshop
The Sagarmatha National Park (Mt Everest,
Central Hymalaya, Nepal)
7. Climate change drivers (temperature…)
Correlation coefficient r = 0.70
Land based
data
0.03 °C y-1
0.03 °C y-1
Tree ring
Model-based
data
i.e. HadCRU TS3
2nd Third Pole Environment (TPE) Workshop
Temperature trend
We observered a
constant increasing rate
of temperature from ‘60s
to ‘90s and then, from
‘90s to ’04.
8. Monthly comparison of temperature
Wednesday, April 08, 2015
9. Climate change drivers (…precipitation)
Precipitation trend:
‘60s to ‘90s- increasing trend of precipitation, and
‘90s to ’08 - decresing trend of precipitation.
2nd Third Pole Environment (TPE) Workshop
10. Mapping and satellite imagery
For this study in Sagarmatha National Park following
maps and satellite images were used:
1960s: India Survey 1960s, scale 1:50,000
1990s: HMG/N official maps 1992, scale 1:50,000
2008: ALHOS 2008 digital satellite imagery
2nd Third Pole Environment (TPE) Workshop
11a. Glaciers
Nearly all (28 out of 29 in SNP) are ‘black glaciers’, known also as Dtype or debris-covered glaciers; these are glaciers in which the ablation
zone is almost entirely covered by surface debris that significantly
reduce the energy exchanges between the ice and the atmosphere.
2nd Third Pole Environment (TPE) Workshop
11b. Glaciers
•
SNP experienced a small net reduction in glacier cover of 19.6 km2 (4.9% in total, -0.15 % per year) from 403.9 km2 at the end of the ‘50s
to 384.6 km2 at the start of the ‘90s.
•
From ‘90s to 2008, SNP experienced an higher net reduction in glacier
cover of 28.4 km2 (-7.0% in total, -0.44% per year)
Western Himalaya
1976-90
1990-03
0.2 % yr-1
0.45 % yr-1
Ye et al, 2006a
Central Tibetan Plateau
1969-92
1992-02
0.1 % yr-1
0.26 % yr-1
Ye et al, 2006b
It should be stressed here that the higher reduction of the glacier might be
because of delay response of glacier to the increasing temperature (more
than 10 years) (Oerlemans, 2005)
2nd Third Pole Environment (TPE) Workshop
11a. Glacial lakes
Number of lakes
(N)
Surface
(km2)
Proglacial
17
1.8
Supraglacial
437
1.4
Glacial
170
4.3
All lakes in SNP
624
7.4
Proglacial:
moraine dammed
Supraglacial: lakes on the glaciers
Glacial:
lakes not connected with
the glaciers
Sagarmatha National Park area: ~ 1250 km2
2nd Third Pole Environment (TPE) Workshop
1 lake per 2 km2 (1.4 x 1.4 km)
12b. Glacial lakes
Changes (% yr-1) among different lake typologies
(Double entrance tables)
2nd Third Pole Environment (TPE) Workshop
13. Lakes quantity: Summary
The Central Himalayan range (Sector 4 South) experiences a constant increased
temperature from the beginning of ‘60s until the last recent years: a rate of 0.030 °C yr-1,
higher if compared with the mean increasing registered for the Northern Hemisphere
(0.013°C yr-1).
The glaciers reacted with a slow reduction until ‘90s, while we observed a fast decreasing of
their surface in the last period. Considering a constant temperature increase, the speeding
up of glaciers can be only explained observing the precipitation reduction.
LAKES COULD BE A CLEARER INDICATORS OF CLIMATE CHANGE. Proglacial and
Supraglacial lakes seem more dependent on temperature change than lake without direct
connections with glaciers. Both of them have increased their surfaces in two periods with the
same order of magnitude answering to a constant temperature raise.
The number of Supraglacial lakes is also enormously increased (from 213 to 436) in the last
period, reacting to an general fragmentation of glacier surfaces occurred in this period.
Finally, the lakes without direct connections with glaciers experienced a big reduction
reacting to the precipitation decreasing.
2nd Third Pole Environment (TPE) Workshop
14. Lakes quality: preliminary evidences on glacial lakes
Upper Pyramid Lake (LCN 9)
Sagarmatha National Park
Significant correlation between chemical
species and the annual mean temperature at
the AWS Pyramid Station
2nd Third Pole Environment (TPE) Workshop
15. Lakes quality (physico-chemical and biological) variability
MODIS 2009 Tibetan Plateau
There are more than 1000
lakes larger then 1 km2 on
Tibetan Plateau and several
thousands including the
surrounding
mountain
chains.
Lakes give an integrated response at basin level (regional answer) to the
natural and anthropogenic pressure (integrated answer).
Where the local anthropogenic pressure are limited (as TPE) and it is
possible to identify using physico-chemical or biological tracers, lakes
can help us to measure the integrated and regional effects of global
change pressure on the environment as or better than other proxy
indicators.
Conclusions
Lakes as relevant indicator of climate change impact on quantity, quality and
biology of the TPE’s water resources
The first step of CCQQB Project is concluded assessing the impact of climate
change pattern (temperature and precipitation) and its impacts on the glacialised
areas.
We get first results on effects of climate change on water quality (i.e. increase of
dissolved ions) in glacial lakes not affected by suspended particulate matter (clear
lakes).
Next step is to valuate the cycle of pollutants (as the trace metals, POPs etc.) as
anthropogenic indicators of the impact on aquatic ecosystems to understood how
their contribution is affecting the biodiversity and functioning of mountain lakes
to distinguish by the impacts of climate change.
In order to characterise the different patterns of the climate change on water resources
in TPE we propose to extend the CCQQB approach to a new reference lakes site in the
Tibetan Plateau.
Thanks for your attention
2nd Third Pole Environment (TPE) Workshop