global warming & its impacts

IMPACTS OF GLOBAL

WARMING ON IRRIGATION

ENGINEERING

CONTENT

Introduction of Global Warming

Causes of Global Warming

Impacts of Global Warming Droughts

Floods

Level Rising Temperatures of Oceans /sea

Tornadoes

Hurricanes

The Melting of Mountain Glaciers

The Reduction of Snow Cover

Coastal Erosion

INTRODUCTION

Global warming is the term used to describe a gradual

increase in the average temperature of the Earth's

atmosphere and its oceans, due to which permanently

change occurs in the Earth's climate.

CAUSES OF GLOBAL WARMING

Most of the climate scientists are agree that the

main cause of the current global warming is due to the

"green house effect“

There may be other causes like

Respiration

Mining activities

Rapid industrialization

Increased in auto mobile use

GREEN HOUSE EFFECT

present in the atmosphere absorbs infrared radiations reflected from the surface

of the earth and heats up the atmosphere.

SOURCES OF GREEN HOUSE GASES

Sunlight’s energy remains trapped in the atmosphere

FLOODS & DROUGHTS

CAUSED BY GLOBAL

WARMING

DROUGHTS CAUSED BY GLOBAL

WARMING

A drought is an extended period of dry weather

caused by a lack of rain

Increased temperatures cause more evaporation

some places will receive greater concentrations of

rain and other places will receive less (droughts)

EFFECTS OF DROUGHTS TO

IRRIGATION

Amount of water in lakes, rivers, and streams

Crop Losses

Drying of Irrigation Canals

Affect the coastal Areas

Cause Heat Waves

Affect LiveStock

HOW FLOOD IS CAUSED BY

GLOBAL WARMING

A flood is an overflow of water that submerges

land which is usually dry

The rate of evaporation from the ocean seems to be

increasing

EFFECTS OF FLOOD TO

IRRIGATION

Embankments of barrages and rivers

Damages underground piping system

Destroy agricultural crops

Affect the water table

Damage Head Canal

Affect whole Irrigation System

CASE STUDY OF 2010 FLOOD

DAMAGES OF 2010 FLOOD

Affects the 79 Districts of Country

20 Million people affected

1600 Casualties

1.89 Million homes Destroyed

Huge Damages of Water Courses, Tube wells

Damage the crops of Approximately

1.32 Million Hectares

CROPS DAMAGES OF 2010 FLOOD

IRRIGATION DAMAGES OF 2010

FLOOD

MAP OF FLOOD AFFECTED AREAS

LEVEL RISING TEMPERATURES OF

OCEANS /SEA

CAUSED BY GLOBAL WARMING

RISING TEMPERATURE OF OCEANS

AND SEA

Rising temperature of ocean and sea may be more significant

than the direct effect of higher temperature.

Because….

• The world's agricultural output is heavily dependent on

irrigation.

• Out of a global cropped area of 1500 million ha, 16% is

irrigated.

• Global warming is likely to have a major impact on the

hydrological cycle and consequently on irrigated agriculture.

RISING TEMPERATURE OF OCEANS

AND SEA

As we have discussed that atmospheric temp raises due to

green house effects so it raises the temp of sea/ocean on the

following two mechanism

Two major mechanisms are causing sea level to rise.

First, shrinking land ice, such as mountain glaciers and polar

ice sheets, is releasing water into the oceans.

Second, as ocean temperatures rise, the warmer water

expands. Trapped within a basin bounded by the continents,

the water has nowhere to go but up. :

RISING TEMPERATURE OF OCEANS

AND SEA

The consequences of sea level rises due to temp include

Threats to coastal communities

Some 40% of the world’s population lives within 62

miles of the ocean.

RISING TEMPERATURE OF OCEANS

AND SEA

Saltwater intrusion

Sea-level rise can mean that saltwater intrudes into

groundwater drinking supplies, contaminates irrigation

supplies, or overruns agriculture fields.

RISING TEMPERATURE OF OCEANS

AND SEA

TORNADOES AND HURRICANES

CAUSED BY GLOBAL

WARMING

Tornadoes:

• A tornado is rapidly spinning air that develops from a

thunderstorms and is on the ground.

• The ingredients for a tornado are a thunderstorm, winds

changing speeds with height and rapidly rising air.

Hurricanes:

• A hurricane is a huge organized thunderstorm

complex that develops over the ocean

• The ingredients are warm ocean water, weak upper

level winds, and low pressure

TORNADOES AND HURRICANES

Comparison between Tornadoes and Hurricanes:

TORNADOES AND HURRICANES

HOW DO TORNADOES FORM?

The formation of tornadoes can be described into 3

steps:

1. Air Rotates Because of Wind Shear

2. Faster Spin Makes a Funnel Cloud

3. The Funnel Rotates and Touches Down

HOW DO HURRICANES FORM?

IMPACTS OF TORNADOES & HURRICANES

Irrigation Systems:

• Damaging winds caused extensive

damage to numerous pivot style irrigation

systems that farmers use to water crops

Flooding:

• Heavy rains and ocean waters brought

ashore by strong winds can cause

flooding in excess of 50 cm (20 in)

over a 24 hour period.

IMPACTS OF TORNADOES & HURRICANES

An abnormal increase in the ocean's

level, sometimes in excess of several

meters high.

As hurricane winds, rainfall, and storm

surge cause direct and indirect effects

on the environment, this can also impact

agriculture.

Storm Surge: Impacts to Agriculture

MELTING OF GLACIERS

CAUSED BY GLOBAL

WARMING

MELTING OF GLACIERS

MELTING OF GLACIERS

Over a Thousand years ago, Asians used to irrigate

their lands by the melted water from glaciers.

During Warm season, snow melts slowly, releasing a

steady flow of water.

Over the last few decades, Glaciers are melting at

a torrid pace as an adverse effect of Global

warming & climate change.

MELTING OF GLACIERS

Effects of Glacier Melting:

Reduced water for agricultural use

Shrinkage of river based irrigated land

Contamination of coastal groundwater supply

More floods & droughts

Mudslides, dam break etc.

MELTING OF GLACIERS

Acc. to WWF, Himalayan Glaciers are retreating

10-15 m/year, causing rivers to be changed into

seasonal streams.

This glacier melting would pose freshwater scarcity

needed for the crop production, thus leading to

food shortage.

The world food security is threatened by the glacier

melting more in Himalayas and Tibet plateau.

MELTING OF GLACIERS

Acc. to IPCC reports, Himalayan glaciers could melt

entirely by 2035.

This melting of glaciers could soon deprive the

major rivers of India, China & Pakistan.

In the Indus, Ganga, Yellow, and Yangtze River

basins, where irrigated agriculture depends heavily

on rivers, the glacier melt will shrink harvests and

could create unmanageable food shortages.

MELTING OF GLACIERS

The Yangtze River in China, is threatened by the disappearance of glaciers which will effect 369m people who rely heavily on rice from fields irrigated with its water.

In the Ganga river alone, the loss of glacier melt water would reduce river flows by two third, causing water shortage for 500m people and 37 per cent of India’s irrigated land.

Similarly, 60% of Pakistan’s people, depend on grain irrigated by the Indus river, which is also dependent on meltwater from Himalayan glaciers, are under threat of food & water scarcity.

COSTAL EROSION AND ITS IMPACTS

ON IRRIGATION

CAUSED BY GLOBAL WARMING

COSTAL EROSION AND ITS

IMPACTS ON IRRIGATION

Erosion: erosion is the action of surface

processes such as water flow or wind

that remove soil, rock or dissolved

material from one location on

the Earth's crust then transport it away

to another location.

Natural rates of erosion are controlled

by the action of geomorphic drivers.

COASTAL EROSION

Coastal erosion, which

occurs on both exposed and

sheltered coasts, primarily

occurs through the action of

currents and waves but sea

level tidal change can also

play a role.

Cont:

Hydraulic action takes place when air in a joint is suddenly

compressed by a wave closing the entrance of the joint. This

then cracks it.

Wave pounding is when the shear energy of the wave hitting

the cliff or rock breaks pieces off.

Cont:

Coastal erosion can pose a

risk to residential

developments, roads,

lifeline utilities and coastal

structures and adversely

affect the irrigation water

and agricultural land.

IMPACTS OF COASTAL EROSION

Danger to life in the case of sudden onset landslide events

Structural damage or destruction of buildings and

infrastructure

Damage or destruction of lifeline infrastructure such as

water, sewage and gas pipes and roads

Loss of land, resulting in coastal cliffs or shorelines

retreating closer to other buildings

Land instability at neighboring slopes and properties

Loss of beach amenity due to cliff collapse or sea wall

construction.

IMPACTS ON IRRIGATION

Increased salinity.

Enhanced waterlogging.

Reduction of irrigation water.

Increased Sedimentation.

Shrinkage of agricultural land.

Shortage of Food.

THANK YOUEACH OF US MUST TAKE STEPS TO PROTECT OUR EARTH FROM GLOBAL WARMING