IB ESS HL HL.a.8 UN conventions and protocols Question Bank
Practise IB ESS HL HL.a.8 by applying un conventions and protocols concepts to exam-style environmental systems questions.
- Syllabus
- First assessment 2026
- Course
- ESS HL
- Level
- HL
Practise IB ESS HL HL.a.8 by applying un conventions and protocols concepts to exam-style environmental systems questions.

Figure:Comparison of the effects of CFCs, HCFCs and HFCs

Figure:HCFCs and HFCs cause less damage than CFCs but still affect the environment
The hole in the ozone layer over Antarctica, discovered in the 1980s, was caused by chlorofluorocarbons (CFCs). The Montreal Protocol requires the use of hydrochlorofluorocarbons (HCFCs) or hydrofluorocarbons (HFCs) instead of CFCs (Figure: Comparison of the effects of CFCs, HCFCs and HFCs). However, these two gases are also linked to environmental problems (Figure: HCFCs and HFCs cause less damage than CFCs but still affect the environment).
Identify one advantage of staggered dates for the phasing out of HFCs for countries at different levels of economic development.
allows less developed countries more time to raise necessary funding; allows less developed countries time to develop/import necessary technology/infrastructure; allows less developed countries time to introduce significant changes in policy/governance; deadlines are more reasonable so more countries are likely to commit to change; issue can start being addressed sooner by more developed countries;
Identify one disadvantage of staggered dates for the phasing out of HFCs for countries at different levels of economic development.
may prolong achievement of complete/global phasing out; may reduce action to a lower priority than necessary in some countries; may prompt some multinational companies to relocate to countries with later deadlines; developed countries, given shorter deadlines, may be more dependent on HFCs so have more to do; countries avoiding early phase out may benefit from production/trade of HFCs; cost of early change/application of untested substitutes may lead to conflict from more developed countries; conflicts arising from different treatments between countries may undermine overall agreement;