Global Climate change represents one of the greatest challenges
facing society and freshwater resources today. It impacts key aspects of everyday
life and puts significant demands on global resources. Increases in population and
economic development have lead to increasing pollution, adding greenhouse gases
such as carbon dioxide, methane, nitrous oxides and fluorinated gases into the atmosphere,
intensifying the greenhouse effect. Here, I explore how climate change effects
freshwater resources in China.
Water shortages could threaten China’s social and economic
development. Projected climate change could affect water availability across
China. China contains 20% of the worlds population but only 7% of its freshwater.
In 2014 eleven out of thirty-one
provinces did not meet the World Bank’s water needs criteria of 1500m3. Low water
pricing has bought on poor water management by disconnecting the market water
prices helping to increase wasteful usage in farming and industry and constant pollution
of the already scarce freshwater resources. A 2009 World Bank report stated that China was
using ten times more water per unit of production than the average
industrialised country. (Arden, 2017).
Climate change has exacerbated the situation. Meltwater from
the Tibetan Plateau, which feeds into the Yangze and yellow rivers,
Climate Model Projections
In the next thirty years, the global climate model predicts
that eastern and central China will experience a hotter and drier climate. It is
predicted that the amount of accessible water could decrease by 20%. According
to the UKMO Hadley climate scenario (1960-2099) between 2061-2099, both air
temperature and rainfall are likely to increase significantly across China. While
more water will become available for most of China during the second half of
the century, northern China is anticipated to experience additional water
stress due to large increases in temperature. (Sun et al., 2002).
How will availability of freshwater resources be impacted by
Precipitation and potential evaporation are the main
climatic drivers controlling freshwater resources. Warmer air can hold much
more water vapour. This can lead to more and heavier rainfall when the air
cools. Heavier rainfall leads to more rapid movement of water from the atmosphere
back to the oceans, reducing the ability to store and use it. Warmer air also
means that snowfall is replaced by rainfall, increasing evaporation rates.
China has to deal with increased and heavier rainfall events,
often leading to flash floods alongside adapting to a drying climate. Floodwater
will often produce many health problems because of damage to water supply
systems and insufficient drinking water supplies. However, the most serious
consequence of flooding is large scale contamination of drinking water. it can
become contaminated with microorganism like bacteria, sewage, heating oil,
agricultural or industrial waste.
Glaciers will play a key role in determining runoff in the
future and a continuing increase in glacial runoff can be expected in response
to warming. However, uncertainties are large as it lies in the vulnerability of
Chinese glaciers to future warming. Runoff from the Tibetan Plateau’s mountains
feeds the largest rivers across Southeast Asia, including the Yangtze, Yellow,
Mekong, Ganges and Indus rivers. If glaciers continue to retreat and snowpack
shrinks atop the plateau, the water supplies of billions of people will be in
danger (Cyranoski, 2005). The exact timing and magnitude of the ‘tipping point’
of each glacier is still uncertain, the projected long-term exhaustion of
glacial water supply should have a considerable impact on the availability of
water for both agricultural and human consumption.
The most important victim in our climate system could be the
summer monsoon. Monsoons play an important role in determining local weather
conditions, including rainfall patterns. The impact of monsoon on the local
weather is different from place to place. In some places it’s just a question
of having a little more or less rain. In other places, it means serious flood
or drought. In summer, the Tibetan plateau heats up more than the Indian Ocean,
leading to a pressure gradient and the flow of the air and moisture from the
ocean. As the land surface absorbs more sunlight than the atmosphere, the
plateau creates a vast area of surface warmer than the air at that elevation,
increasing the land–ocean pressure gradient and intensifying the monsoon.