Kyoto Protocol 
United Nations Framework Convention on Climate Change

This international agreement, which builds on the United Nations Framework Convention on Climate Change, sets legally binding targets and timetables for cutting the greenhouse-gas emissions of industrialized countries. It covers more than 160 countries globally and over 55% of global greenhouse gas (GHG) emissions.

ISO 14000 Environmental management standards 

The ISO 14000 environmental management standards exist to help organizations minimize how their operations negatively affect the environment (cause adverse changes to air, water, or land), comply with applicable laws, regulations, and other environmentally oriented requirements, and continually improve on the above.

Greenhouse Gas Protocol Initiative 

This is the most widely used international accounting tool for government and business leaders to understand, quantify, and manage greenhouse gas emissions. A partnership between the World Resources Institute and the World Business Council for Sustainable Development.

It consists of two modules:
Corporate Accounting and Reporting Standards 
Methodologies to business and other organizations to inventory and report all of the GHG emissions they produce.

Project Accounting Protocol and Guidelines 
Accounting tool for quantifying the greenhouse gas benefits of climate change mitigation projects.