7. Sustainability, Environmental Policy, and Solutions

Sustainability means meeting the needs of the present without compromising the ability of future generations to meet their own needs (Brundtland Commission, 1987). It has three interconnected pillars: environmental protection, economic development, and social equity.

The three Rs — waste reduction hierarchy:
In order of preference:

1. Reduce — use less in the first place; the most effective option.
2. Reuse — find new uses for items before discarding.
3. Recycle — process materials back into raw materials. Better than landfill but requires energy.

(4. Recover — waste-to-energy incineration; controversial.)
(5. Dispose — landfill; least preferred.)

Carbon footprint:
The total greenhouse gas emissions caused directly and indirectly by a person, organization, or product, expressed in CO₂ equivalent (CO₂e). Major contributors for an individual in wealthy countries: transportation (especially flying), diet (beef is the most carbon-intensive food), home energy use.

International climate agreements:

• Kyoto Protocol (1997): first binding international treaty requiring developed countries to cut GHG emissions. The US signed but did not ratify it.
• Paris Agreement (2015): 196 nations committed to keeping warming "well below 2°C above pre-industrial levels" and pursuing 1.5°C. Each country sets its own nationally determined contribution (NDC). Not legally binding on emission targets.
• Montreal Protocol (1987): addressed the separate problem of the ozone hole — banned chlorofluorocarbons (CFCs) that deplete stratospheric ozone. Widely considered the most successful international environmental treaty.

Policy tools:

• Carbon tax: puts a price on CO₂ emissions, incentivizing businesses and individuals to reduce.
• Cap-and-trade (emissions trading): sets a total cap; companies buy and sell permits — achieves emission reductions at lowest cost.
• Regulations / standards: fuel economy standards, energy efficiency standards, building codes.
• Subsidies: for renewable energy, electric vehicles — making cleaner options cheaper.

Sustainable development goals (SDGs):
The UN's 17 SDGs (2015–2030) include clean energy (SDG 7), climate action (SDG 13), life below water (SDG 14), and life on land (SDG 15) — frameworks for international cooperation on sustainability.

Systems thinking:
Environmental problems are interconnected. Solving one in isolation can create others (e.g., biofuels reduce fossil fuel use but compete with food crops). Effective solutions require understanding the whole system.