Effects on The Hydrosphere

Summary Presentation

This presentation contains all the information detailed below, in the form of slides

Climate Change Effects - Water

Introduction

~97% of all Earth’s water is oceanic and saline
Most of the remaining 3% of freshwater is locked up in land ice, glaciers, and permafrost
This makes up the majority of the Earth’s cryosphere (the portions of the Earth’s water that exist in solid form on the surface)
Aside from cryospheric water, a comparatively small amount of freshwater is stored in the form of groundwater, lakes, soil, wetlands, rivers, biomass, and the atmosphere

Water storage in the Cryosphere

Available evidence suggests cryosphere, in general, is reducing in size
However, patterns and trends are not uniform
At altitudes above 400 metres in Antarctica, glaciers are not thinning and may even be gaining mass
- This is because snowfall is increasing across the Antarctic Peninsula (as warmer air can hold more moisture)
However, this increased snowfall in upper regions is not enough to offset melting at lower altitudes
Overall, about four-fifths of all glaciers across the Antarctic Peninsula are receding
The changes affecting different frozen water stores in the cryosphere are noted below. In many cases, there is a reported reduction in the mass balance of the ice store. The partial or complete losses of these stores may cost humans sea-level rise and the threatened loss of water supply in heavily populated regions

Ice Caps and Alpine Glaciers

Ice caps occur all over the world, from polar regions to mountainous areas such as the Himalayas, the Rockies, the Andes, and the Southern Alps of New Zealand. The Furtwangler Glacier on Kilimanjaro is the last remaining ice cap in Africa, but is melting quickly and may soon disappear

Alpine glaciers are thick masses of ice found in deep valleys or in upland hollows. These glaciers are particularly important in the Himalayas where meltwater from 15,000 Himalayan glaciers supports perennial rivers such as the Indus, Ganges, and Brahmaputra - these are relied on by millions of people across South Asian countries (India, Pakistan, Nepal, Bhutan, Bangladesh)
Glacial retreat clearly evident in aerial photographs of retreating glacier snouts and vanishing ice, such as Wolverine Glacier in Alaska or Argentina’s Upsala Glacier (pictured upper-right). China’s Urumqi No. 1 glacier (pictured lower-right) has reportedly lost more than 20% volume since 1962

Permafrost

Vast permafrost ring around the Arctic Ocean has already begun to thaw in places where temperature has risen by several degrees since the 1960s
This melting is releasing large amounts of carbon dioxide and methane, potentially affecting the global climate even more

Greenland and Antarctic Ice Sheets

An ice sheet is a mass of glacial land ice extending more than 50,000 sq.km. The two major ice sheets on Earth today cover most of Greenland and Antarctica and together contain more than 99% of freshwater ice on Earth
- Antarctic ice sheet contains as much area as that of USA + Mexico combined; Greenland ice sheet is much smaller
Overall, Antarctica is losing more ice than it gains each year; deficit is 70 gigatonnes per year (1 gigatonne is 1 billion tonnes) - warmer surface air temperatures around the northern Antarctic Peninsula are having a dramatic effect.
Scientists estimate if the entire Greenland ice sheet melted, the sea level would rise by about 6 metres; if the entire Antarctic ice sheet (pictured twice left) melted, sea level would rise about 60 metres

Greenland and Antarctica Ice Shelves

Ice shelves are floating platforms of ice that form where glaciers and ice sheets move out into the oceans
- They exist mostly in Greenland and Antarctica, as well as in the Arctic near Canada and Alaska
The Antarctic ice sheet is melting from below due to increased upwelling of relatively warm, deep water coming into contact with the underside of ice shelves

Arctic Sea Ice

Within the Arctic Circle lie northern parts of Russia, Canada, Alaska (USA), Greenland, and Scandinavia, as well as the Arctic Ocean, parts of which remain covered with sea ice all year

Within the Arctic Circle lie northern parts of Russia, Canada, Alaska (USA), Greenland, and Scandinavia, as well as the Arctic Ocean, parts of which remain covered with sea ice all year.
Future temperature rises projected to be at greatest latitudes and in recent decades the Arctic has heated twice as fast as rest of the world.
Some experts predict the region will be entirely ice free by 2050.
- Temperatures 20ºC higher than usual in late 2016 suggest it may occur even sooner.

Increasing sea level

Historically, water levels have always been higher during warm periods and lower during cold periods. A warmer climate results in higher water levels for two reasons, and both are related to temperature, but in different ways.

Two causes of rise in sea level

Thermal Expansion

Melting of Ice Caps

Series of eustatic sea level rise caused by thermal expansion and melting of ice caps

Global average sea level rise of approximately 3mm per year
In total, global sea level has risen by 200 mm since 1900
Significant glacier and permafrost meltwater runoff will produce another metre of sea-level rise by around 2200(even if GHG emissions are significantly cut)
Without any action to cut emissions, large scale melting of the Greenland and Antarctica ice sheets could contribute to 7m and 60m rises respectively(but this will take hundreds of year)

Case study: Bangladesh

Bangladesh

Bangladesh is a South Asian country neighbouring India and Myanmar. Bangladesh is a home for 164.7million people which make the country one of the most densely populated countries in the world. The population density of the country is 1,252 people per square kilometre, and it is ranked at the 13th highest population density

Geographic characteristics of Bangladesh

Bangladesh is an unique country in terms of its geographical characteristics. Bangladesh is the country where world's biggest river delta is located, Ganges delta. Ganges delta is a delta connected to Ganges, Meghana, and Brahmaputra rivers merge and connect to the Bay of Bengal. Unsurprisingly, 79% of the land of the country is covered with the delta. Most Bangladeshis live along delta areas where alluvial delta soils provide most of the best cultivation in the country. It is estimated that around 400million people live in the delta areas and approximately 156million of them are Bangladeshi. Generally, the land is low as majority of the country is delta. Nearly one-quarter of Bangladesh is less than seven feet above the sea level. More widely, two-thirds of the country is less than 15 feet above sea level.

Flooding and Bangladesh

The Himalayas is located in the north side of Bangladesh. Himalayas is where rivers merge to the Ganges delta start. The alpine glaciers of Himalayas melt and they becomes stream of the rivers, the glaciers melted at the consistent melting rate when there were no irregular climate changes in the past. Nowadays, the glaciers melt faster than any period of time before, it is because of the global warming, warmer temperature accelerates the melting rate of the glaciers. As a result, more water gets into the rivers and merges in the delta as the glaciers melt at a higher rate, it causes more frequent, irregular, and violent floods in the delta area. Recently, one-quarter of Bangladesh is inundated annually in an average year and there is a severe flood that covers over 60% of the country in every four or five years. The annual flood causes fatal soil erosions around the delta areas, for example, Sandwip Island, near Chittagong, has lost 90% of its original 23-square-miles, mostly in the last two decades. Due to the erosions caused by the floods, between 50,000 and 200,000 people are displaced annually. Climate refugees usually fail to adopt to new environments and most of them are ended up in the slum areas of Chittagong and Dhaka, the capital of Bangladesh. More tragically, climate refugees are not welcomed in India and Myanmar as Bangladesh is a predominantly Muslim country.

Impacts of sea level rise in Bangladesh

Bangladesh is a clean country in terms of carbon emission, the country only produces 0.3% of world's total annual carbon emission. However, Bangladesh is one of the most impacted countries by the consequences of the global warming as majority of the land is low altitude land. The biggest consequence that impact the country is the rise in sea level, sea level has raised significantly in past few decades. The rise in sea level will have critical impacts on the land of Bangladesh. The rise in sea level has already started impacting the land. Sea water gradually started to get into the land and it makes the vegetation in the costal area almost impossible. Due to the rise, the impacts of tides and cyclones have been reinforced as more water can have impacts on the land. In a long term, a 1m rise in sea level will cause a loss of 17.5%(25000Km^2) of Bangladesh land and 60%(71million) of the population will be affected. (2003)(OECD)

Infographic and Analysis

Bangladesh Documentary climate change

This YouTube video the impacts of climate changes on Bangladesh. The video mentions displaced people due to the climate changes, lands that are not suitable for vegetation due to salt water, and damages of cyclones.

Sea level rise - ESA

Summary:

This YouTube clip explains the general information of sea level rise, cause and effect. It also explains why and how water is not rising uniformly across the globe, due to gravity and current.

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