Lakes are changing worldwide: Human activities to blame
Date:
October 18, 2021
Source:
Vrije Universiteit Brussel
Summary:
Worldwide, lake temperatures are rising and seasonal ice cover is
shorter and thiner. This effects lake ecosystems, drinking water
supply and fishing. International research now shows that these
global changes in lake temperature and ice cover are not due to
natural climate variability. They can only be explained by massive
greenhouse gas emissions since the Industrial Revolution. To
demonstrate this, the team has developed multiple computer
simulations with models of lakes on a global scale, on which
they ran a series of climate models. The researchers found clear
similarities between the observed changes in lakes and model
simulations of lakes in a climate influenced by greenhouse gas
emissions. Besides measuring the historical impact of climate
change, the team also analyzed various future climate scenarios.
FULL STORY ========================================================================== International research led by Luke Grant, Inne Vanderkelen and Prof Wim
Thiery of the VUB research group BCLIMATE shows that global changes in
lake temperature and ice cover are not due to natural climate variability
and can only be explained by massive greenhouse gas emissions since the Industrial Revolution. The influence of human-induced climate change is
evident in rising lake temperatures and in the fact that the ice cover
forms later and melts sooner.
========================================================================== "These physical properties are fundamental to lake ecosystems," says
Grant, a researcher at VUB and lead author of the study. "As impacts
continue to increase in the future, we risk severely damaging lake
ecosystems, including water quality and populations of native fish
species. This would be disastrous for the many ways in which local
communities depend on lakes, ranging from drinking water supply to
fishing." The team also predicted future development under different
warming scenarios.
In a low-emission scenario, the average warming of lakes in the future is estimated to stabilise at +1.5DEGC above pre-industrial levels and the
duration of ice cover to be 14 days shorter. In a high-emission world,
these changes could lead to an increase of +4.0 DEGC and 46 fewer days
of ice.
At the beginning of the project, the authors observed changes in lakes
around the world: temperatures are rising and seasonal ice cover is
shorter. However, the role of climate change in these trends had not
yet been demonstrated.
"In other words, we had to rule out the possibility that these changes
were caused by the natural variability of the climate system," says
fellow VUB researcher and study co-author Vanderkelen.
The team therefore developed multiple computer simulations with models
of lakes on a global scale, on which they then ran a series of climate
models. Once the team had built up this database, they applied a
methodology described by the Intergovernmental Panel on Climate Change
(IPCC). After determining the historical impact of climate change on
lakes, they also analysed various future climate scenarios.
The results show that it is highly unlikely that the trends in lake temperatures and ice cover in recent decades can be explained solely
by natural climate variability. Moreover, the researchers found clear similarities between the observed changes in lakes and model simulations
of lakes in a climate influenced by greenhouse gas emissions.
"This is very convincing evidence that climate change caused by humans has already impacted lakes," says Grant. Projections of lake temperatures and
ice cover loss unanimously indicate increasing trends for the future. For
every 1DEGC increase in global air temperature, lakes are estimated
to warm by 0.9DEGC and lose 9.7 days of ice cover. In addition, the
analysis revealed significant differences in the impact on lakes at the
end of the century, depending on the measures taken by humans to combat
climate change.
"Our results underline the great importance of the Paris Agreement
to protect the health of lakes around the world," says Wim Thiery,
VUB climate expert and senior author of the study. "If we manage
to drastically reduce our emissions in the coming decades,
we can still avoid the worst consequences for lakes worldwide." ========================================================================== Story Source: Materials provided by Vrije_Universiteit_Brussel. Note:
Content may be edited for style and length.
========================================================================== Journal Reference:
1. Grant, L., Vanderkelen, I., Gudmundsson, L. et al. Attribution
of global
lake systems change to anthropogenic forcing. Nature Geoscience,
2021 DOI: 10.1038/s41561-021-00833-x ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2021/10/211018112456.htm
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