Turning Knowledge into Action
Introduction
Root Causes of Climate Change are rapid population growth and rising economic development increase energy demand.
• Fossil fuel combustion, deforestation, and inefficient agriculture have raised greenhouse gas (GHG) levels to unprecedented heights.
• If nothing is done to break the links between population growth, poverty, energy use, and greenhouse gas emissions, the world will soon experience changes in climate that present a major threat to society and the environment.
The Deep Roots of Climate Change
Population of the world reached 8 billion in 2022 and is growing at over 1% a year.
By 2050, 9 billion people want cheap energy to power their lives.
The world in 2050 will be hot and crowded, and the energy demand will be as much as 50% higher than today.
Population Growth and Poverty as Drivers of Climate Change
Energy is essential for modern living.
It provides clean water, lighting, refrigeration, safe cooking, and sanitation.
Access to energy also helps reduce disease, infant mortality, and unemployment, and improves education.
Wealthy nations can invest in clean and renewable energy.
Developing nations often rely on cheaper fossil fuels or biomass, which worsen climate change but meet urgent energy needs.
The world must find ways to meet growing energy demand while reducing fossil fuel use.
Although there’s been progress in renewable energy adoption, it’s too slow to prevent dangerous global warming.
A global, cooperative effort is essential to tackle both climate change and energy poverty simultaneously.
Who Will Take the Lead?
Under the Berlin Mandate, developed nations acknowledged responsibility for elevated atmospheric CO₂ and pledged to reduce emissions
Developing nations resisted binding targets, citing threats to economic growth.
Paris Agreement Framework Established transparent monitoring and reporting of Nationally Determined Contributions (NDCs).
Enables incremental strengthening of each country’s emissions commitments as technology costs fall.
Developed countries must address strategic and economic priorities while supporting developing countries’ right to growth.
Sustained, ambitious NDCs are crucial; failure risks inadequate collective action and more severe climate impacts.
Five contrasting greenhouse gas emissions and warming scenarios to 2100 with different trajectories that depend on our actions today.
Shading represents model uncertainty and warming is relative to preindustrial temperatures.
Do Nations Have a Right to Pursue Economic Growth?
Delaying emissions cuts may benefit growth now but incur higher mitigation costs later.
Climate change impacts will hit the least developed countries hardest.
Reducing greenhouse-gas intensity (GHG per economic output) is crucial for developing nations’ future stability.
Developed countries must cut absolute emissions; developing countries focus on lowering GHG intensity.
Emissions attribution is complex: wealthy nations often outsource manufacturing.
Responsibility can be shared between the producer (manufacturing country) and the consumer (importing country).
Global economies are linked; helping neighbors reduce emissions ultimately benefits everyone.
Balancing the right to grow with avoiding future climate-driven economic losses is essential.
Energy Demand and Greenhouse Gas Emissions
Emissions began with deforestation and land clearing for agriculture (burning undergrowth).
Post–World War II Acceleration
Cheap coal and oil fueled rapid industrial growth in the U.S.,USSR, Japan, and Europe during the 1950s.
Late 20th Century Surge in Developing Countries
Exceptional economic growth in China, India, and other emerging economies drove emissions even higher.
Developing-country emissions projected to be 114% above 2000 levels by 2030.
Per Capita Disparities
Despite growth, an average person in a developed nation (e.g., the U.S.) uses 5 × more energy than someone in a developing country.
Understanding historical and regional emission trends is essential for crafting fair, effective climate policies.
Global Emissions
Fossil Fuel Combustion (73% of Emissions)
Coal, oil, and natural gas combustion supply most energy for electricity and transportation.
Accounts for 73% of all anthropogenic greenhouse gas emissions (Figures 10.7–10.9).
Other Emission Sources (27%)
Land use change & forestry (LUCF)
Agriculture
Waste disposal
Greenhouse Gas Breakdown
CO₂: 73% of global GHGs
CH₄: 15%
N₂O: 7%
CO₂ Emissions by Sector (of total CO₂)
Electricity & heat generation: 25%
Transport (fossil fuels): 14%
Industry (direct emissions): 21%
Emissions from the United States
Economic & Demographic Context
4.25% of global population
Supports 16% of world GDP
Produces 15% of global GHGs (~6.56 GtCO₂e)
Per Capita Emissions
>16 tCO₂/person/year – the highest worldwide
Primary Energy Consumption
Largest oil consumer globally
2nd largest coal consumer (after China)
CO₂ Emissions by Sector
Transport: 29% (≈2× global average)
Electricity & Heat: 25%
Industry: 23%
Commercial & Residential: 13%
Agriculture: 10%
Land Use & Forestry: 12%
Emissions from China
Population & Economy
18% of world’s population
18% of global GDP
Emissions
27% of global GHGs (14 Gt CO₂e) – more than U.S. + other developed nations combined
Per capita: 7.1 t CO₂/person/yr (Figure 10.1)
Energy Consumption
World’s largest coal consumer (6× U.S. coal use)
Largest oil importer (2× U.S. oil use)
Emissions from Bangladesh
Population & Density
2% of global population
Highest density: 1,265 /km² (3,289 /mi²)
Economy & Emissions
0.21% of global GDP
0.5% of global GHGs (0.209 Gt CO₂e)
Per capita: 0.66 t CO₂/person/yr
Vulnerability
Despite low emissions, faces first and worst climate impacts
Facing an Uncertain Future
Adaptive Capacity Factors
Linked to population size, poverty index, economic growth rate, and energy supply.
U.S. & China: Strategic dominance and resources for energy transitions.
Bangladesh: Prioritizes economic growth to reduce poverty; lifted millions via cheap energy.
Bangladesh’s Progress
85% electricity access; ~6% annual GDP growth.
Current fuel mix: Natural gas with plans for three new coal plants.
Path Forward
Must shift from coal to lower-carbon sources, renewables, and energy efficiency.
Needs external aid for technology transfer and investment.
The Paris Agreement framework offers support but action is urgent to prevent future economic setbacks.
Why Should We Worry About Emissions?
2022 Emissions: ~10.23 Gt C (37.5 Gt CO₂) added to the atmosphere
2050 Projection: >11.7 Gt C (43 Gt CO₂) per year
Scale: 1 Gt = 1 billion tonnes
International Dimension:
Must balance emission reductions with social equity across nations
Intergenerational Impact:
Emissions today have influenced climate and ocean acidity for centuries
Non-Linear Risk:
The danger of sudden, irreversible climate shifts grows every year emissions remain unchecked
Can Emissions Decrease without International Action?
Market-Driven Transition
By 2050, climate impacts will be undeniable; fuel prices will rise as resources decrease.
Renewables become cost-competitive; public demand shifts.
Population growth in major economies (China, India) stabilizes, leading to eventual emissions decline.
Insufficient Timing
Waiting for autonomous market and demographic shifts means too late: irreversible climate change locked in by mid-century.
IPCC Emissions Targets
To limit warming to 1.5°C: 45% reduction from 2010 levels by 2030; net zero by 2050.
To limit warming to 2°C: 25% reduction by 2030; net zero by 2070.
Current trajectory: ~36 Gt CO₂ by 2030; >43 Gt by 2050—driven by coal and gas in developing nations.
Urgent Need for Cooperation
Replace fossil fuels with clean, renewable energy.
Reverse deforestation to create carbon sinks.
Modernize agriculture to capture more carbon.
Leadership from the U.S., EU, China, and India is critical—vulnerable countries cannot adapt alone.