The environment for permafrost in Daisetsu Mountains in Japan is
projected to decrease significantly

Date:
July 30, 2021
Source:
National Institute for Environmental Studies
Summary:
Areas with climatic conditions suitable for sustaining permafrost
in the Daisetsu Mountains are projected. The size of the area in
the Daisetsu Mountains where climatic conditions were suitable for
permafrost were estimated to be approximately 150 km2 in 2010. Under
the business-as- usual scenario, this area is projected to disappear
by around 2070. Under the low-carbon scenario consistent with Paris
target scenario, the area is projected to decrease to approximately
13% of 2010 by 2100.



FULL STORY ========================================================================== Areas with ground temperatures that remain below 0DEGC for more than
two years are referred to as permafrost, and approximately one quarter
of the Northern Hemisphere and 17% of the Earth's exposed land surface
is permafrost.

Permafrost is found in mountainous areas as well as in high-latitude
tundra and taiga regions. Recent observations have shown that the
permafrost in mountainous areas is thawing in the European Alps,
Scandinavia and on the Tibetan Plateau.


==========================================================================
The islands that make up Japan form a long arc that extends from tropical regions in the south to Palearctic regions in the north. Permafrost
has been reported to exist in the Daisetsu Mountains, Mt. Fuji and
Mt. Tateyama. The Daisetsu Mountains on the northern island of Hokkaido,
which are known to support a variety of alpine plants and animals, are
also a valuable natural resource that is visited by numerous climbers
every year. However, there is some concern that the thawing of permafrost
will have a major impact on this mountain ecosystem. No projections
of future permafrost distribution have been undertaken in East Asia,
including in Japan, to date.

In this study, by applying the statistical method developed in a
previous study for estimating the permafrost distribution to outputs from bias-corrected and downscaled climate model with a 1 km resolution for
the area of interest, we investigated the climatic conditions required
to sustain permafrost in the Daisetsu Mountains.

Researchers have studied the climate conditions suitable to maintain
permafrost in the Daisetsu Mountains. The region of the climate conditions suitable to maintain permafrost starts to decrease significantly in size
from around 2000, and under both the low-carbon scenario consistent with
Paris target (RCP2.6) and busines-as-usual scenario (RCP8.5). The steep
decline in the region at the end of the 20th century occurs because
the surface air temperature increases significantly from around the
year 2000 onward. The size of the area in the Daisetsu Mountains where
climatic conditions were suitable for permafrost were estimated to be approximately 150 km2 in 2010. Under the RCP8.5 scenario, this area
is projected to disappear by around 2070. Under the RCP2.6 scenario,
the area is projected to decrease to approximately 20 km2 by 2100.

The finding that the climatic conditions of the Daisetsu Mountains are projected to shift towards conditions where permafrost will disappear regardless of the climate scenario used, indicates the importance
of impact assessments and developing adaptation measures to climate
change. Thawing of permafrost can have a significant impact on the surface vegetation and alpine ecosystems. Previous studies have shown that the
thawing of permafrost can have a variety of adverse effects, including
lowering groundwater levels and replacement of alpine meadows by steppes, extensive desertification such as that in the eastern and western parts
of the Tibetan Plateau, and a decrease in species diversity due to
warming. Moreover, thawing of the frozen ground reduces the stability
of the ground in mountain regions, potentially increasing the frequency
and magnitude of rock falls and landslides, which may affect the safety
of trekkers that visit the Daisetsu Mountains annually. In order to deal
with these problems, it is very important to monitor the environmental
changes in mountainous areas. In addition to accurately monitoring changes
in mountain environments, providing local governments with appropriate
measures to prepare for major future environmental changes, as shown in
this study, is an important issue for the future.

========================================================================== Story Source: Materials provided by National_Institute_for_Environmental_Studies. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Tokuta Yokohata, Go Iwahana, Toshio Sone, Kazuyuki Saito, Noriko N.

Ishizaki, Takahiro Kubo, Hiroyuki Oguma, Masao Uchida. Projections
of surface air temperature required to sustain permafrost and
importance of adaptation to climate change in the Daisetsu
Mountains, Japan. Scientific Reports, 2021; 11 (1) DOI:
10.1038/s41598-021-94222-4 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/07/210730165447.htm

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