World Environment Day was accompanied June 5 by a call to “kick the habit” of producing carbon dioxide, the principal gas associated with climate change. The theme “Kicking the CO2 Habit – Towards a Low-Carbon Economy” was adopted by the United Nations Environment Program (UNEP), because, according to the agency's chief, Achim Steiner, what is needed are actions to reduce, halt and reverse global increases in emissions of greenhouse-effect gases.

Many scientists believe that climate change is the main threat humanity faces this century. It is the gradual warming of the Earth's atmosphere, which in the last 250 years has accumulated gases released in large part by human activities, like industry, motorized transportation, livestock production and deforestation.

These gases, like CO2, aggravate the atmosphere's natural greenhouse effect, trapping the heat of the Sun's rays. The main source of CO2 is the combustion of coal, gas and petroleum.

UNEP pushed for steps to reduce individual and national production of greenhouse gases, such as switching to more efficient lightbulbs, unplugging unused electronic equipment, seeking less-polluting forms of transportation, replacing coal as a source of generating electricity and developing clean and renewable energy sources.

New Zealand was chosen to host the June 5 events because it was among the first countries to commit to going “carbon neutral”: a zero balance in the difference between the greenhouse gases produced and sequestered or offset.