Greenhouse Gasses Global Warming and Its Impact

Dr. Shahid Amjad

Institute of Business Management

(IoBM)

The Greenhouse Gasses

Six main greenhouse gases are

• carbon dioxide (CO2),

• methane (CH4) (which is 20 times as potent a greenhouse gas, as carbon dioxide)

• nitrous oxide (N2O), plus

• three fluorinated industrial gases: – hydrofluorocarbons (HFCs),

– perfluorocarbons (PFCs) and

– sulphur hexafluoride (SF6).

• Water vapor is also considered a greenhouse gas.

• The greenhouse effect is the rise in temperature on Earth as certain gases in the atmosphere trap energy.

• Climate changes are long term process while weather is short term that varies from one place to another and is determined by temperature and various meteorological conditions such as. – Precipitation – Wind, – glaciations – Extreme events, typhoon, hurricanes etc.

• The most important attribute of climate change is temperature variation. (caused by excessive amounts of green house gases)

• The evidences gathered by climatologists from tree rings, changes in sea level etc have shown that our planet has maintained an average temperature within a limited range, but seems to be changing continuously.

• Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C

• Thus to predict future impacts of anthropogenic activities on the global climate and consequently on key environmental parameters, a mathematical model needs to be developed that explains the past.

In the 1880 - 1935 period, the temperature anomaly was consistently negative. In contrast, since 1980 the anomaly has been consistently positive. The 1917 temperature anomaly (-0.47oC) was the lowest year on record. Since 1917, global temperature has warmed, with the most recent years showing the highest anomalies of +0.6oC in the past 120 years.

What is the Greenhouse Effect? • The term greenhouse is used in conjunction with the

phenomenon known as the greenhouse effect. • 70% of energy our planet received from the sun drives the

earth’s weather and climate, as it heats up the earth’s /ocean surface; while the rest is absorbed by clouds, oceans and land masses.

• In turn, the earth radiates 30% energy back into space; • Some atmospheric gases (carbon dioxide, water vapor, and

other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse;

• Trapping heat is good to a certain extent (avg. Global temp. 14 C), if no heat was trapped the avg. Global temp -19 C).

• Thus the atmosphere has a big role for maintaining the right temperature for sustaining life on earth

GHE#1 - natural

Earth’s Natural Greenhouse Effect

GHE#2 - humans Human-caused Global Warming

GHE#3 - text The science of global warming is based on well-

understood physical principles. There is NO

scientific debate about this!

Due to human activities, there are now 40% more

greenhouse gases in the atmosphere than there

were a hundred years ago. (5 bn tons of

excessive CO2 )

The Earth has already warmed as the

consequence of this, and scientists expect that

the next 20 to 100 years the world will warm a lot

more! (1-5 C). For every 1 C rise, 7% increase in

water vapor. (IPCC)

The climate has always varied in the past. How is this any different?

• Throughout Earth’s history the climate has varied, sometimes considerably.

• Past warming does not automatically mean that today’s warming is therefore also natural.

• Recent warming, has been shown to be due to human industrialization processes.

Warming of Climate

• Warming of the climate is definitely occurring and can be observed by the:

– Increases in global sea and air temperatures

– Widespread melting of snow and ice in the northern areas.

– Rising global sea level.

– Pakistan’s contribution towards Green House Gases (GHS) is negligible (<0.8%).

What is Global Warming and Climate Change?

• Global warming and climate change refer to an increase in average global temperatures. Natural events and human activities are believed to be contributing to an increase in average global temperatures. This is caused primarily by increases in “greenhouse” gases such as Carbon Dioxide (CO2).

• A warming planet thus leads to a change in climate which can affect weather in various ways.

Atmospheric CO2 Concentrations

Global Surface Temperatures

What are the main indicators of Climate Change?

• The US agency, the National Oceanic and

Atmospheric Administration (NOAA), suggests

• 10 indicator,

• 7 indicators that would be expected to increase in a warming world. While 3 indicators (ice and snow) would be on the decline.

Based on comprehensive data from multiple sources, there are reportedly 10 measurable planet-wide features used to gauge global temperature changes. The relative movement of each of these indicators proves consistent with a warming world. Seven indicators are rising:

1. air temperature over land, 2. sea-surface temperature, 3. air temperature over oceans, 4. sea level, 5. ocean heat, 6. humidity and 7. tropospheric temperature in the “active-weather” layer of the atmosphere

closest to the Earth’s surface. • Three indicators are declining: 1. Arctic sea ice, 2. glaciers and 3. spring snow cover in the Northern hemisphere.

“Glaciers and sea ice are melting, heavy rainfall is intensifying and heat

waves are more common. And, as the new report tells us, there is now evidence that over 90 percent of warming over the past 50 years has gone into our ocean.”

• In addition to the natural fluxes of carbon through the Earth system, anthropogenic (human) activities, particularly fossil fuel burning and deforestation, are also releasing carbon dioxide into the atmosphere.

• When we mine coal and extract oil from the Earth’s crust, and then burn these fossil fuels for transportation, heating, cooking, electricity, and manufacturing, we are effectively moving carbon more rapidly into the atmosphere than is being removed naturally through the sedimentation of carbon, ultimately causing atmospheric carbon dioxide concentrations to increase.

• Also, by clearing forests to support agriculture, we are transferring carbon from living biomass into the atmosphere (dry wood is about 50 percent carbon).

• The result is that humans are adding ever-increasing amounts of extra carbon dioxide into the atmosphere. Because of this, atmospheric carbon dioxide concentrations are higher today than they have been over the last half-million years or longer.

The above covers hundreds of thousands of years and shows how atmospheric CO2 levels have dramatically increased in recent years. If we “zoom” in on just the past 250 years, we see the above rising CO2 pattern

values shown represent Carbon Gigatons being absorbed and released

This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution:

Sea level rise • Republic of Maldives:

Vulnerable to sea level rise

• Global sea level rose about 17 centimeters (6.7 inches) in the last century.

• The rate in the last decade, however, is nearly double that of the last century.

Global temperature rise

• major global surface temperature show that Earth has warmed since 1880.

• Most of this warming has occurred since the 1970s, with the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the past 12 years.

• Even though the 2000s witnessed a solar output decline resulting in an unusually deep solar minimum in 2007-2009, surface temperatures continue to increase.

Warming oceans • The oceans have

absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 degrees Fahrenheit since 1969.

Shrinking ice sheets

• The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost 150 to 250 cubic kilometers (36 to 60 cubic miles) of ice per year between 2002 and 2006,

• while Antarctica lost about 152 cubic kilometers (36 cubic miles) of ice between 2002 and 2005.

Flowing meltwater from the Greenland ice sheet

Arctic sea ice

• Declining Arctic sea ice

• Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.

The extent of floating sea ice in the Arctic Ocean, as measured at its annual minimum in September, showed a steady decline between 1980 and 2009.

Extreme events

• The number of record high temperature events in the United States, Europe has been increasing, while the number of record low temperature events has been decreasing, since 1950.

• The U.S. and Asian countries have also witnessed increasing numbers of intense rainfall events.

Ocean acidification

• The carbon dioxide content of the Earth’s oceans has been increasing since 1750, and is currently increasing about 2 billion tons per year. This has increased ocean acidity by about 30 percent.

Ocean Acidification; consumption of carbonate ions impede calcification. Source: Pacific Marine Environment Laboratory, NOAA

• More CO2 in the atmosphere means more CO2 in the ocean; • Atmospheric CO2 is dissolved in the ocean, which becomes more acidic; and • The resulting changes in the chemistry of the oceans disrupts the ability of

plants and animals in the sea to make shells and skeletons of calcium carbonate, while dissolving shells already formed.

• Scientists have found that oceans are able to absorb some of the excess CO2 released by human activity. This has helped keep the planet cooler than it otherwise could have been had these gases remained in the atmosphere.

• However, the additional excess CO2 being absorbed is also resulting in the acidification of the oceans: When CO2 reacts with water it produces a weak acid called carbonic acid, changing the sea water chemistry.

• One example of recent findings is a tiny sand grain-sized plankton responsible for the sequestration of 25–50% of the carbon the oceans absorb is affected by increasing ocean acidification. This tiny plankton plays a major role in keeping atmospheric carbon dioxide (CO2) concentrations at much lower levels than they would be otherwise so large effects on them could be quite serious.

• Each day, the oceans absorb 30 million tonnes of CO2 and if forams can no longer play their role in this carbon storage system then atmospheric concentrations of CO2 could skyrocket with calamitous effects on the global climate system.

• There is absolutely no controversy about the basic chemistry of additional CO2 increasing ocean acidity.

• The oceans naturally absorb carbon from the atmosphere and have now absorbed about a third of the total amount of human emissions. This additional carbon has altered the oceans' chemistry, making them 25 to 30 percent more acidic because the extra CO2 combines with carbonate ions in seawater, forming carbonic acid.

• Shell-forming creatures - mussels, corals, hard planktons, shrimps and many more - all need those carbonate ions to build their shells.

Rank Event When

Occurred Event Description

More

Information

1

Russian -

European -

Asian Heat

Waves

Summer

A severe summer spawned drought, wildfires

and crop failures across western Russia,

where more than 15,000 people died. All-time

high temperatures occurred in many cities and

nations in the region. China faced locust

swarms during July.

NCDC

Global

Hazards

2

2010 as

[near]

warmest

year on

record

calendar

year

According to NOAA, the globally-averaged

temperature for 2010 will finish among the two

warmest, and likely the warmest, on record.

Three months in 2010 were the warmest on

record for that month.

NCDC

Global

Report

3 Pakistani

Flooding

Late

July –

August

2010

Rainfall related to the Asian Monsoon was

displaced unusually westward, and more than

a foot of rain fell across a large area of the

Upper Indus Valley. Subsequent flooding

down the Indus River killed 1,600 people and

displaced millions.

NCDC

Global

Hazards,

NASA

Imagery

Adaption to Climate Change

• Adaptation is necessary not only to respond to the projected changes in climate but also because climate change is already affecting many ecosystems.

• Adaptation activities can have negative, neutral or positive impacts on biodiversity.

• Adaptation activities that can have a negative impact on biodiversity include: the construction of artificial coastal protection, changed water management practices, and new cultivation methods such as mariculture or aquaculture, that is introduced to coastal ecosystems, new species can be a potential to become invasive species threatening and destabilizing established ecosystems.

Impact of Climate Change on Pakistan • Forecast models for climate change and increasing temperatures for

Pakistan predicts: • increased flooding, • Increase in Poverty • rock avalanches, • Disruptions in water resource as the Himalayan glaciers continue to melt. • Floods exceeding design parameters could destroy the dams, barrages, and

other fixed-capacity irrigation infrastructure on which the country’s agriculture depends.

• The risk of hunger will also increase because of declining crop productivity owing to heat stress.

• Other areas of concern include: i. the further intrusion of saline water along the Sindh coastal zone due to an

accelerated rise in sea level; ii. more and stronger cyclones caused by rising sea surface temperatures

that will affect Karachi and other coastal settlements; iii heat strokes brought on by summer temperature spikes; and iv. the spread of disease vectors encouraged to breed in stagnant water

bodies during mild winters.