Environment - About Climate change

1. UNIT III CLIMATE CHANGE
Global warming and changing environment –
Ecosystem changes – Changing blue-green-
grey water cycles – Water scarcity and water
shortages – Desertification.

2. Global warming and changing
environment
• Global warming is the gradual warming of the
earth surface because of the continuous
increasing in the temperature of the atmosphere
due to some natural and human made causes.
• The main cause of the global warming is the
collection of greenhouse gases in the earth
atmosphere which work as a blanket and trap lots
of heat causing rise in temperature of the
atmosphere

3. What are the greenhouse Gases?
Water vapour
Carbon dioxide
Methane
Nitrous oxide
Ozone

4. Effects of Global Warming
Increased Temperature
Habitat Damage and
Species Affected Changes in Water Supply
Rising Sea Level

5. Ecosystem changes
Climate is an important environmental influence on ecosystems. Changing
climate affects ecosystems in a variety of ways.
Increasing global temperature means that ecosystems will change;
some species are being forced out of their habitats because of changing
conditions, while others are flourishing. Secondary effects of global warming,
such as lessened snow cover, rising sea levels, and weather changes, .may
influence not only human activities but also the ecosystem.

6. natural water cycle
• Evaporation is when the sun shines on water and heats it, turning it
into gas called water vapour which rises into the air.
• Transpiration is when the sun warms people, plants and animals
and they release water vapour into the air.
• Condensation is when the water vapour in the air cools and turns
back into a liquid, forming tiny water droplets in the sky.
• Precipitation is when water droplets fall from the sky as rain, snow
or hail.
• Run-off is when water flows over the ground and into creeks, rivers
and oceans.
• Infiltration is when water falls on the ground and soaks into the
soil.
• Percolation is when water seeps deeper into tiny spaces in the soil
and rock.

8. Changing blue-green-grey water
cycles
Green water = rainwater that falls on the fields and has been
absorbed by the plant. This makes up the green water footprint
of the crop.
Blue water = water from rivers, lakes and groundwater used by
the crop to grow. This makes up the blue water footprint of the
crop.
Grey water = water taken to reduce any pollution caused while
growing the plant to original levels.

9. Green and Blue Water Cycle

10. This flowchart shows the % of rainfall that moves through the different hydrological
systems and how much is then used for rainfed and irrigated agriculture.

11. Water scarcity and water shortages
• Water scarcity is the lack of fresh water resources to
meet water demand. It affects every continent and was listed
in 2019 by the World Economic Forum as one of the
largest global risks in terms of potential impact over the next
decade.
• The total amount of easily accessible freshwater on Earth, in
the form of surface water (rivers and lakes)
or groundwater (in aquifers, for example), is 14.000 cubic
kilometres (nearly 3359 cubic miles). Of this total amount,
'just' 5.000 cubic kilometres are being used and reused by
humanity.

12. • Water scarcity can be a result of two mechanisms: physical (absolute)
water scarcity and economic water scarcity, where physical water
scarcity is a result of inadequate natural water resources to supply a
region's demand, and economic water scarcity is a result of poor
management of the sufficient available water resources.
Effects of water shortages?
The effects of water scarcity can be grouped into these 4
broad areas— Health, Hunger, Education, and Poverty.

13. Desertification.
• Desertification is a type of land degradation in which a
relatively dry area of land becomes a desert, typically losing
its bodies of water as well as vegetation and wildlife. It is
caused by a variety of factors, such as through climate
change (particularly the current global warming)[3] and
through the overexploitation of soil through human activity.

14. • Climatic variations’ and ‘Human activities’ can be
regarded as the two main causes of desertification
• Climatic variations: Climate change, drought, moisture
loss on a global level
• Human activities : These include overgrazing,
deforestation and removal of the natural vegetation
cover , agricultural activities in the vulnerable
ecosystems of arid and semi-arid areas, which are thus
strained beyond their capacity. These activities are
triggered by population growth, the impact of the
market economy, and poverty.