A scientist will spend Earth Day explaining how an essential ingredient in the world's food supply is also adding to global warming.

Dr. James N. Galloway, Associate Dean for the Sciences, University of Virginia, is to give a public lecture on Thursday at the Bermuda Institute of Ocean Sciences.

Entitled 'The Nitrogen Dilemma: Feeding the World or Protecting the Environment?', Dr. Galloway will run through the challenges in using nitrogen fertiliser and its detrimental effects on the Earth.

Dr. Galloway will illustrate how nitrogen is lost to the environment during food and energy production, and describe the impacts on humans and the ecosystem.

He will also demonstrate how the choices people make can determine the severity of the effects.

Nitrogen is an essential part of amino acids that form the basis of all life, and is therefore needed in the growth of food.

Since the early 20th century the Haber-Bosch process has provided a virtually inexhaustible supply of nitrogen fertiliser, through the production of ammonia.

This is crucial to the food supply of half the Earth's population, but most of this nitrogen is lost to the environment.

Together with the nitrogen released by fossil fuel combustion it contributes to smog, the greenhouse effect, ecosystem eutrophication (increase in concentration of chemical nutrients), acid rain and the Nitrogen Cascade (loss of stratospheric ozone).

The challenge for the 21st century will be balancing the production of food with minimising the negative effects on the environment. Scientists therefore need to make the public and policymakers aware of the nitrogen issue.

Dr. Galloway will conclude his lecture by exploring an integrated nitrogen management plan for the Island.

The lecture takes place at 6.30 p.m. on Thursday in Hanson Hall at BIOS, Ferry Reach.

l Tickets are $15 for members, $20 for non-members. There will be a cash bar from 6pm. RSVP to: Vanessa.Shorto@bios.edu