Which international agreement aims to limit global temperature rise below 2°C?

The correct option is Paris Agreement.

To understand why this is the correct answer, let's look at the primary objectives of the agreements listed in the options:
1. Paris Agreement (2015): This is a legally binding international treaty on climate change. Its central goal is to limit global warming to well below 2°C (preferably to 1.5°C) compared to pre-industrial levels.
2. Montreal Protocol (1987): This agreement focuses on protecting the ozone layer by phasing out the production and consumption of ozone-depleting substances (such as chlorofluorocarbons or CFCs).
3. Kyoto Protocol (1997): This was an earlier international treaty that committed industrialized countries and economies in transition to limit and reduce greenhouse gas emissions in accordance with agreed individual targets. Unlike the Paris Agreement, it did not explicitly set the universal temperature threshold of keeping warming well below 2°C.
4. Rio Declaration (1992): Formulated at the Earth Summit, this document consists of 27 principles intended to guide future sustainable development around the world, rather than setting specific temperature limits.

Therefore, the Paris Agreement is the specific international accord designed to limit global temperature rise below 2°C.