The U.N. climate panel says a review of geo-engineering will be part of its next major report in 2013.

SOLAR REFLECTORS

Some of the geo-engineering schemes proposed include:

- Ocean fertilization. Large areas are sprinkled with iron or other nutrients to artificially spur growth of phytoplankton, which soak up carbon dioxide. But this could trigger harmful algal blooms, soak up nutrients and kill fish and other animals.

- Spray seawater into the atmosphere to increase the reflectivity and condensation of clouds so they bounce more sunlight back into space.

- Placing trillions of tiny solar reflectors out in space to cut the amount of sunlight reaching the Earth.

- Artificial volcanoes. Tiny sulfate particles or other materials are released into the stratosphere to reflect sunlight, simulating the effect of a major volcanic eruption.

- Carbon capture and storage. Supported by a number of governments and involves capturing CO2 from power stations, refineries and natural gas wells and pumping it deep underground.

Mooney said the U.N. Convention on Biological Diversity (CBD) should expand its de-facto moratorium on ocean fertilization agreed in 2008 to all geo-engineering, although the proposal was resisted by some countries, including Canada, earlier this year.

Canada said in Nagoya that it would work with the CBD.

"Canada was simply concerned about the lack of clarity on definitions including what activities are included in 'geo-engineering'," Cynthia Wright, head of the delegation, said in an email response.

"Canada shares concerns of the international community about potential negative impacts of geo-engineering on biodiversity and is willing to work with other CBD Parties to avoid these impacts," she said.

Environmentalists said geo-engineering went against the spirit of the Nagoya talks, which aims to set new targets for 2020 to protect nature, such as setting up more land and marine protected areas, cutting pollution and managing fishing.

"We are certainly in favor of more (geo-engineering) research, as in all fields, but not any implementation for the time being because it's too dangerous. We don't know what the effects can be," said Francois Simard of conservation group IUCN.

"Improving nature conservation is what we should do in order to fight climate change, not trying to change nature."

(Reporting by Chisa Fujioka; Editing by David Fogarty)

Copyright © 2007 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon.