Glossary beginning with V

Click one of the letters above to go to the page of all terms beginning with that letter.


Volatile Organic Compounds (VOCs)

Any one of several organic compounds which are released to the atmosphere by plants or through vaporization of oil products, and which are chemically reactive and are involved in the chemistry of tropospheric ozone production. Methane , while strictly falling within the definition of a VOC, is usually considered separately.


An opening in the earthÕs crust that allows gas, ash or molten lava to be ejected from the earthÕs surface.

Voluntary commitments

A draft article considered during the negotiation of the Kyoto Protocol that would have permitted developing countries to voluntarily adhere to legally binding emissions targets. The proposed language was dropped in the final phase of the negotiations. The issue remains important for some delegations and continues to be discussed, currently in the context of the Bali Action Plan, in terms of what constitutes ÒvoluntaryÓ.

Voluntary Measures

Measures to reduce GHG emissions that are adopted by firms or other actors in the absence of government mandates. Voluntary measures help make climate -friendly products or processes more readily available or encourage consumers to incorporate environmental values in their market choices.


The degree of sensitivity to the impact of hazards .

Vulnerable Populations

Populations susceptible to the damaging effects of a hazard, for a variety of physical, social, economic, and environmental reasons.

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