CSS Environmental Sciences Climate Change Syllabus

Approximately what was the pre-industrial atmospheric CO2 concentration, and roughly where is it today?

Pre-industrial CO2 was about 280 parts per million (ppm); it has now exceeded about 420 ppm.

List four key indicators of a changing climate.

Rising global average surface temperature, rising sea level, shrinking glaciers and ice sheets, declining Arctic sea ice, ocean acidification and warming, and more frequent extreme weather events.

By roughly how much has global average surface temperature risen since the pre-industrial era?

By about 1.1 to 1.2 degrees Celsius above pre-industrial (late 19th-century) levels.

What is ocean acidification and what causes it?

Ocean acidification is the ongoing decrease in seawater pH caused by the ocean absorbing excess atmospheric CO2, which forms carbonic acid and harms shell-forming and coral organisms.

What two processes drive sea-level rise under global warming?

Thermal expansion of warming seawater, and the addition of water from melting land ice (glaciers and the Greenland and Antarctic ice sheets).

What is the temperature target of the 2015 Paris Agreement?

To hold global average warming well below 2 degrees Celsius above pre-industrial levels, and to pursue efforts to limit it to 1.5 degrees Celsius.

Define carbon footprint.

A carbon footprint is the total amount of greenhouse gases, expressed as carbon dioxide equivalent (CO2e), emitted directly and indirectly by an individual, organization, product, or activity.

What does the unit CO2-equivalent (CO2e) express?

CO2e expresses the combined warming impact of different greenhouse gases as the amount of CO2 that would produce the same warming, by multiplying each gas's mass by its global warming potential.

Name three major contributors to a typical individual's carbon footprint.

Transportation (driving and flying), home energy use (electricity and heating), and diet (especially meat and dairy), along with consumption of goods and services.

What is the difference between carbon footprint mitigation by offsetting versus reduction?

Reduction lowers the actual emissions at the source (e.g. using less energy); offsetting compensates for emissions by funding equivalent reductions elsewhere (e.g. tree planting, renewable projects).

How does climate change threaten the world's glaciers, and why does it matter for water supply?

Rising temperatures accelerate glacier melt and retreat, reducing long-term meltwater storage; many rivers depend on glacial melt, so shrinking glaciers threaten dry-season water supply for millions.

Why is the Hindu Kush-Himalaya region called the 'Third Pole' or 'Asia's water tower'?

Because it holds the largest store of ice and snow outside the polar regions and feeds major rivers (Indus, Ganges, Brahmaputra) that supply water to hundreds of millions of people.

What is a Glacial Lake Outburst Flood (GLOF) and why is it a climate hazard?

A GLOF is a sudden, catastrophic release of water from a glacial lake when its natural dam fails; warming increases glacier melt and lake formation, raising GLOF risk in mountain regions like northern Pakistan.

How does climate change affect agriculture and food security?

It alters growing seasons, reduces crop yields through heat and water stress, increases pest and disease pressure, causes more droughts and floods, and threatens food availability, access and prices.

What is the general effect of higher temperatures on staple cereal crops like wheat?

Heat stress during the grain-filling stage shortens the growing period and reduces yields; for wheat, each degree of warming can cut global yields by several percent.

How can climate change reduce the nutritional quality of crops?

Elevated atmospheric CO2 can lower the protein, zinc and iron content of staple crops such as wheat and rice, worsening 'hidden hunger' even where yields are maintained.

Name three human health impacts of climate change.

More heat-related illness and deaths (heatstroke), wider spread of vector-borne diseases (malaria, dengue), and water-borne diseases and malnutrition from floods, droughts and crop failures.

How does climate change expand the range of vector-borne diseases like malaria and dengue?

Warmer temperatures and changing rainfall expand the geographic and seasonal range of mosquitoes and shorten pathogen incubation, allowing diseases to reach higher altitudes and new regions.

What is a climate refugee or climate-displaced person?

A person forced to leave their home or region due to climate-related impacts such as sea-level rise, drought, floods or desertification that make the area uninhabitable.

How does sea-level rise threaten human settlements?

It causes coastal flooding, erosion, saltwater intrusion into freshwater and farmland, and displacement of populations in low-lying coastal cities and deltas.

Why is Pakistan considered highly vulnerable to climate change despite low emissions?

Pakistan contributes under 1 percent of global emissions but ranks among the most climate-vulnerable countries due to glacier-fed rivers, monsoon dependence, heatwaves, floods, droughts, and limited adaptive capacity.

What were the 2022 Pakistan floods and their significance for climate vulnerability?

Monsoon rains and glacier melt in 2022 caused catastrophic flooding that submerged about one-third of the country, affected over 33 million people, and caused tens of billions of dollars in losses, highlighting Pakistan's exposure.

Which sectors are most threatened by climate change in Pakistan?

Water resources (Indus river system), agriculture (the economic backbone), energy, coastal areas (Indus delta, Karachi), and public health, given heat extremes and water scarcity.

What makes Pakistan's water security particularly fragile under climate change?

Pakistan depends heavily on a single river system (the Indus) fed by Himalayan/Karakoram glaciers and monsoon, has limited storage capacity, and is already a water-stressed country approaching scarcity.

What is the difference between climate change mitigation and adaptation?

Mitigation reduces or prevents greenhouse gas emissions to limit warming (e.g. renewables, efficiency); adaptation adjusts systems and behaviour to cope with the impacts already occurring (e.g. flood defences, drought-resistant crops).

Give four examples of climate change adaptation strategies.

Building flood defences and improved drainage, developing drought- and heat-tolerant crop varieties, efficient irrigation and water storage, early-warning systems, mangrove and forest restoration, and climate-resilient infrastructure.

What is an ecosystem-based adaptation (EbA) approach? Give an example.

EbA uses biodiversity and ecosystem services to help people adapt to climate impacts. Example: restoring mangroves to buffer coasts against storm surges and sea-level rise.

What is climate vulnerability defined as in the IPCC framework?

Vulnerability is the propensity to be adversely affected; it is a function of exposure (degree of climate stress), sensitivity (how affected the system is), and adaptive capacity (ability to cope and adjust).

What is the difference between climate change resilience and adaptive capacity?

Adaptive capacity is the ability of a system to adjust and prepare for change; resilience is the capacity to absorb shocks, recover, and continue functioning after a climate disturbance.

What major national policy and program has Pakistan adopted for climate adaptation and mitigation?

Pakistan adopted the National Climate Change Policy (2012, updated) and large-scale afforestation drives such as the Billion/Ten Billion Tree Tsunami to enhance carbon sinks and resilience.