temperature climatology over the Himalayas for the
present climate was simulated exceptionally well even
though these RCMs showed a significant cold bias
(Nengker et al. 2018). These RCMs showed larger
uncertainty of 1–3.6 °C for simulated temperature in
the CORDEX South Asia historical experiments than
that of the observations in the Himalayan water towers
(e.g. Indus, Ganges and Brahmaputra river basins;
Mishra 2015). This evaluation also showed that the
RCMs exhibited large cold bias (6–8 °C) and were not
able to reproduce the observed warming in the
Himalayan water towers. The downscaled seasonal
mean temperature in this multi-RCM ensemble was
found to have relatively larger cold bias than their
driving CMIP5 AOGCMs over the hilly sub-regions
within the Hindu Kush Himalayan region (Sanjay
et al. 2017b). Also, these downscaled CORDEX South
Asia RCMs and their driving CMIP5 AOGCM
experiments consistently showed substantial cold (6–
10 °C) biases for the observed climatology of temperature over the Himalayan watersheds of Indus basin
(Jhelum, Kabul and upper Indus basin; Hasson et al.
2018).
2.3.1 Mean Temperature
The CORDEX South Asia multi-RCM ensemble mean
projected long-term (2070–2099) annual warming exceeds
4 °C over most parts of India except the southern peninsula,
relative to the reference period 1976–2005 under the high
(RCP8.5) emission scenario, with relatively higher change
exceeding 5 °C projected in the semi-arid north-west and
north India (Fig. 2.7).
The geographical patterns of long-term change remain
below 2 °C relative to the reference period under the low
(RCP2.6) emission scenario over most parts of India. The
projections of mid-term (2040–2069) change in these
CORDEX South Asia multi-RCM ensemble mean indicate
modest sensitivity to alternate RCP scenarios over the Indian
land area. The projected mid-term annual warming exceed
1 °C over most parts of the country, with higher warming
exceeding 2 °C projected in the north-west and north India
under the medium (RCP4.5) emission scenario (Fig. 2.7).
The summer monsoon temperature projections by a small
subset of the CORDEX South Asia RCMs had indicated
mean warming of more than 1.5 °C over the central and
northern parts of India for the period 2031–2060 under this
medium emission scenario (Sanjay et al. 2017a).
The CORDEX South Asia multi-RCMs had provided
relatively better confidence than their driving CMIP5
AOGCMs in projecting the magnitude of seasonal warming
for the hilly sub-region within the Karakoram and
north-western Himalaya, with a higher projected change of
5.4 °C during winter than of 4.9 °C during summer monsoon season by the end of the twenty-first century under the
high (RCP8.5) emissions scenario (Sanjay et al. 2017b).
The CORDEX South Asia RCMs and their ensemble had
projected statistically significant strong rate of warming
(0.03–0.09 °C per year) across all seasons and RCPs over
the Indian Himalayan region (Dimri et al. 2018a). The seasonal response to warming with respect to elevation was
found to be substantial with December–January season followed by October–November showing the highest rate of
warming at higher elevation sites such as the western
Himalayas and northern part of central Himalayas.
The earlier assessment of temperature projections for
India using the CMIP5 multi-model and multi-scenario
ensemble had also suggested that generally in future the
northern part of the country will experience higher warming
compared to the southern peninsula (Chaturvedi et al. 2012).
It was assessed that the areas in the Himalayas and Kashmir
will be particularly subject to large warming to the tune of
8 °C in RCP8.5 by 2099 relative to the pre-industrial baseline (the 1880s). It was concluded that this assessment of a
broad range of temperature projections for India, ranging
from 1 to 8 °C during the period 1880–2099 under different
RCP scenarios indicated that these regional climate change
projections were associated with a range of limitations and
uncertainties—driven mainly by the climate model and
future scenario uncertainties (Chaturvedi et al. 2012). Also,
an earlier study using multiple CMIP5 model outputs together with a single model ensemble assessed that for temperature in most regions within India the component of
uncertainty due to model spread tends to be larger than that
arising due to natural internal variability, and tends to grow
with time (Singh and AchutaRao 2018).
A consistent and robust feature across the downscaled
CORDEX South Asia RCMs is a continuation of warming
over India in the twenty-first century for all the RCP scenarios (Fig. 2.8). The CORDEX South Asia historical RCM
simulations capture the observed interannual variations and
the warming trend reasonably well. The all India averaged
annual surface air temperature increases are similar for all
the RCP scenarios during the first decade after 2005. The
warming rate depends more on the specified greenhouse gas
concentration pathway at longer time scales, particularly
after about 2050. The multi-RCM ensemble mean under
RCP2.6 scenario stays around 1.5 °C above 1976–2005
levels throughout the twenty-first century, clearly demonstrating the potential of mitigation policies. The ensemble
32
J. Sanjay et al.
present climate was simulated exceptionally well even
though these RCMs showed a significant cold bias
(Nengker et al. 2018). These RCMs showed larger
uncertainty of 1–3.6 °C for simulated temperature in
the CORDEX South Asia historical experiments than
that of the observations in the Himalayan water towers
(e.g. Indus, Ganges and Brahmaputra river basins;
Mishra 2015). This evaluation also showed that the
RCMs exhibited large cold bias (6–8 °C) and were not
able to reproduce the observed warming in the
Himalayan water towers. The downscaled seasonal
mean temperature in this multi-RCM ensemble was
found to have relatively larger cold bias than their
driving CMIP5 AOGCMs over the hilly sub-regions
within the Hindu Kush Himalayan region (Sanjay
et al. 2017b). Also, these downscaled CORDEX South
Asia RCMs and their driving CMIP5 AOGCM
experiments consistently showed substantial cold (6–
10 °C) biases for the observed climatology of temperature over the Himalayan watersheds of Indus basin
(Jhelum, Kabul and upper Indus basin; Hasson et al.
2018).
2.3.1 Mean Temperature
The CORDEX South Asia multi-RCM ensemble mean
projected long-term (2070–2099) annual warming exceeds
4 °C over most parts of India except the southern peninsula,
relative to the reference period 1976–2005 under the high
(RCP8.5) emission scenario, with relatively higher change
exceeding 5 °C projected in the semi-arid north-west and
north India (Fig. 2.7).
The geographical patterns of long-term change remain
below 2 °C relative to the reference period under the low
(RCP2.6) emission scenario over most parts of India. The
projections of mid-term (2040–2069) change in these
CORDEX South Asia multi-RCM ensemble mean indicate
modest sensitivity to alternate RCP scenarios over the Indian
land area. The projected mid-term annual warming exceed
1 °C over most parts of the country, with higher warming
exceeding 2 °C projected in the north-west and north India
under the medium (RCP4.5) emission scenario (Fig. 2.7).
The summer monsoon temperature projections by a small
subset of the CORDEX South Asia RCMs had indicated
mean warming of more than 1.5 °C over the central and
northern parts of India for the period 2031–2060 under this
medium emission scenario (Sanjay et al. 2017a).
The CORDEX South Asia multi-RCMs had provided
relatively better confidence than their driving CMIP5
AOGCMs in projecting the magnitude of seasonal warming
for the hilly sub-region within the Karakoram and
north-western Himalaya, with a higher projected change of
5.4 °C during winter than of 4.9 °C during summer monsoon season by the end of the twenty-first century under the
high (RCP8.5) emissions scenario (Sanjay et al. 2017b).
The CORDEX South Asia RCMs and their ensemble had
projected statistically significant strong rate of warming
(0.03–0.09 °C per year) across all seasons and RCPs over
the Indian Himalayan region (Dimri et al. 2018a). The seasonal response to warming with respect to elevation was
found to be substantial with December–January season followed by October–November showing the highest rate of
warming at higher elevation sites such as the western
Himalayas and northern part of central Himalayas.
The earlier assessment of temperature projections for
India using the CMIP5 multi-model and multi-scenario
ensemble had also suggested that generally in future the
northern part of the country will experience higher warming
compared to the southern peninsula (Chaturvedi et al. 2012).
It was assessed that the areas in the Himalayas and Kashmir
will be particularly subject to large warming to the tune of
8 °C in RCP8.5 by 2099 relative to the pre-industrial baseline (the 1880s). It was concluded that this assessment of a
broad range of temperature projections for India, ranging
from 1 to 8 °C during the period 1880–2099 under different
RCP scenarios indicated that these regional climate change
projections were associated with a range of limitations and
uncertainties—driven mainly by the climate model and
future scenario uncertainties (Chaturvedi et al. 2012). Also,
an earlier study using multiple CMIP5 model outputs together with a single model ensemble assessed that for temperature in most regions within India the component of
uncertainty due to model spread tends to be larger than that
arising due to natural internal variability, and tends to grow
with time (Singh and AchutaRao 2018).
A consistent and robust feature across the downscaled
CORDEX South Asia RCMs is a continuation of warming
over India in the twenty-first century for all the RCP scenarios (Fig. 2.8). The CORDEX South Asia historical RCM
simulations capture the observed interannual variations and
the warming trend reasonably well. The all India averaged
annual surface air temperature increases are similar for all
the RCP scenarios during the first decade after 2005. The
warming rate depends more on the specified greenhouse gas
concentration pathway at longer time scales, particularly
after about 2050. The multi-RCM ensemble mean under
RCP2.6 scenario stays around 1.5 °C above 1976–2005
levels throughout the twenty-first century, clearly demonstrating the potential of mitigation policies. The ensemble
32
J. Sanjay et al.