Hundreds of landmarks from Paris' Eiffel Tower to the Seattle Space Needle will dim their lights on Saturday, as people around the world go briefly off-grid to mark Earth Hour with candlelight and barbecues.

The 60-minute annual campaign organised by the conservation group WWF encourages citizens, communities, businesses and organisations to switch the lights off for an hour from 8:30 pm to highlight the plight of planet Earth.

Thousands of people flocked to Mont Saint-Michel on Saturday to watch what they hoped would be a "tide of the century" surround the picturesque landmark on France's northern coast.

Perched on a rocky island topped with a Gothic Benedictine abbey, the Unesco World Heritage Site is exposed to some of Europe's strongest tides.

Without reforms, the world will be plunged into a water crisis that could be crippling for hot, dry countries, the United Nations warned Friday.

In an annual report, the UN said abuse of water was now so great that on current trends, the world will face a 40-percent "global water deficit" by 2030 -- the gap between demand for water and replenishment of it.

The Eiffel Tower disappeared behind a brown smog on Wednesday as Paris and much of northern France suffered a spike in pollution.

"The pollution levels are consistent. If we don't go over the alert level, we won't be far away," said Airparif, the body responsible for monitoring air quality in the greater Paris region. 

The Harvard president told students at one of China's most prestigious universities Tuesday that academic institutions must be unfettered places where every topic can be raised and every question asked to help tackle challenges such as climate change.

The comments by Drew Gilpin Faust were part of a 30-minute speech at Beijing's Tsinghua University on climate change in which she urged universities in the two countries to collaborate on research and on teaching the next generation how to deal with climate change.

Time is running out for the world to achieve a climate change agreement, the president of the European Parliament said Tuesday ahead of a key United Nations meeting in Paris later this year.

"We have to recognise that it is five minutes to midnight, and that the goals we have defined are not European, American or Chinese," Martin Schulz told reporters during a visit to China.

Scientists have discovered two pathways that are likely channeling warm ocean water under a massive Antarctic glacier, which could contribute to rising global sea levels, a study revealed Tuesday.

The 120-kilometer (75 miles) long Totten Glacier, more than 30 kilometers wide, is the largest in East Antarctica and melting more quickly than others in the area.

Vanuatu's President Baldwin Lonsdale said Monday climate change was a key factor in the devastation wrought on the Pacific nation by Super Cyclone Pam, which left six dead and 30 injured in the capital Port Vila alone.

Super Cyclone Pam smashed into the island archipelago late Friday, bringing sustained winds of more than 250 kilometers (155 miles) per hour and causing widespread damage.

In response to the emerging evidence that climate change could have a major global impact, the United Nations Framework Convention on Climate Change (UNFCCC) was adopted in 1992 in Rio de Janeiro.

The ultimate objective of the Convention is the stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous human-induced interference with the climate system. The Convention recognizes that developed countries are responsible for the largest share of historical and current global emissions of greenhouse gases and hence, should take the lead in combating climate change.

Like all the countries in the world, Lebanon contributes to climate change through emitting greenhouse gases from energy, transport, waste and wastewater, forestry, industry and agriculture. Lebanon is also very vulnerable to the adverse impacts of climate change on its environment, economy and society.

Lebanon’s total emission of greenhouse gases is 18.5 million tonnes of Carbon Dioxide (CO2) equivalent. This constitutes 0.07% of the world’s emissions.