vulnerable –adj. easily hurt or harmed
legally binding – adj. enforceable by law
optimistic –adj. hopeful and confident about the future
achieve –v. reach or get something by effort or skill
avert catastrophic damage – phrase. to avoid a terrible disaster and damage
pledge – n. promise or agreement
emission (s) –n. act of producing or sending out energy or gas
renewable energy – n. sustainable energy that comes from the natural environment