Following is a selection of quotes from politicians, activists, business executives and scientists about expectations for the upcoming Rio Summit.

The once-in-a-decade gathering from June 20-22 will turn the spotlight on the planet's environment, poverty eradication, social equity and the green economy.

"We have a difficult mission, of proposing a new model for growth that does not seem too vague or idealistic... We have to make proposals bearing in mind that millions and millions of people do not have access to the minimum conditions for life. Today, because of the international crisis, in developed countries, millions and millions of people are losing their rights, their jobs."

- Brazilian President Dilma Rousseff

"I hope that Rio+20 will become the Tahrir Square of the global environmental crisis and that international public opinion will be able to tell leaders that they cannot brush off the science. They cannot lower expectations in the face of a crisis worsening every day."

- Brazilian activist and former presidential candidate Marina Silva, referring to the crucible of the Egyptian revolution

"The world has changed profoundly over the past 20 years, with a booming middle class, where we are consuming more, using more energy, and putting more pressure on natural resources. Poverty is on the decline, but inequality is on the rise. Rio is an opportunity to move sustainability toward the center of the political and economic agenda."

- Manish Bapna, interim head of US thinktank, the World Resources Institute (WRI)

"We can choose to rebalance the use of resources to a more egalitarian pattern of consumption, to reframe our economic values to truly reflect what our consumption means for our planet and to help individuals around the world to make informed and free reproductive choices. Or we can choose to do nothing -- and to drift into a downward vortex of economic, socio-political and environmental ills, leading to a more unequal and inhospitable future."

- Sir John Sulston, who steered a report on population and sustainability for Britain's Royal Society

"What I expect from Rio is the joint perception that we urgently have to overhaul our rapacious model of economic development. The risk from Rio is disappointment, which would legitimise the blind preference for short-termism and inertia."

- Laurence Tubiana, head of French thinktank Institute of Sustainable Development and International Relations (IDDRI)

"The more biodiversity we lose, the more vulnerable we are to climate change, as well as food, water and energy crises. Our big wish for Rio+20 is that governments and businesses see the need to invest in nature and do so fast. Nature... should be included in all development plans."

- Julia Marton-Lefevre, director general of the International Union for Conservation of Nature (IUCN)

"Factoring in the cost of environmental inputs (in the prices of goods and services) does not yet exist. This is the area where we hope to make progress in Rio+20."

- Marina Grossi, president of the Brazilian Industrial Centre for Sustainable Development (CEBDS), gathering 73 corporations

"We can no longer carry on as if the planet's natural capital is boundless and free. The point of no return is looming. Business can do its part, but governments have to set clear rules"

- Philippe Joubert, adivsor to the World Business Council for Sustainable Development (WBCSD)

"We can start by making sure we measure what matters. Moving beyond GDP (as the sole benchmark of progress) would be a good next step, abolishing fossil fuel subsidies and putting a significant and rising price on carbon."

- Camilla Toulmin, director of the International Institute for Environment and Development (IIED) in London

"Governments have failed to enact and implement land laws to protect (indigenous peoples and communities) against the intense pressure of economic development driving the global land grab... The Rio+20 summit should call on governments to enforce community land rights and propose the development of an innovative private-public partnership to finance tenure reform."

- Andy White of land-rights campaign group Rights and Resources Initiative (RRI)

Rio Summit: The world in figures
Paris (AFP) June 11, 2012 - Following is a snapshot of the world ahead of the UN's June 20-22 Rio Summit on sustainable development.

- POPULATION: Seven billion today, a doubling since 1950, and set to rise to 9.3 billion by 2050, of which two-thirds will live in cities. The population in poor countries has increased more than fourfold since 1961. Forty percent of the world's population today now lives within 100 kilometres (62 miles) of the shoreline.

- ECOLOGICAL FOOTPRINT: Mankind today is gobbling up 50 percent more of the biosphere for our resources and waste than it can sustain. Brazil, China, India and Indonesia have seen their per-capita footprint increase by two-thirds over the past half century. The United States and China together use up nearly half of the global biocapacity. In per capita terms, rich countries' footprints are around four or five times greater than that of poor economies. The hefiest impacts per capita are made by Qatar, Kuwait and the United Arab Emirates respectively.

- POVERTY: The number of people living on $1.25 (one euro) a day fell from 1.9 billion in 1990 to 1.289 billion in 2008, or 22 percent of the developing world. For the first time in 20 years, the proportion of Africans living in extreme poverty has fallen, with 47 percent living below this threshold in 2008 compared with 52 percent in 2005. But 43 percent of the population in developing countries live on less than $2 (1.6 euros) a day.

- BASIC SERVICES: More than 2.5 billion people are in need of decent sanitation and nearly one in 10 has yet to gain access to "improved" drinking water, as defined under the UN's 2015 development goals. 1.4 billion people have no mains electricity.

- CLIMATE CHANGE: Emissions of man-made greenhouse gases are scaling new peaks and the early signs of climate change are already visible, in glacier melt, changed snowfall and habits of migrating species. Current pledges for curbing carbon emissions will lead to warming of 3.5 degrees Celsius (6.3 degrees Fahrenheit), massively overshooting the UN target of 2 C (3.6 F) and enhancing the risk of flood, drought, storms and rising seas.

- BIODIVERSITY: In 2002, the international community pledged to slow biodiversity decline by 2010, and incorporated the target into the UN's Millennium Development Goals. But the drop-off has accelerated, driven especially by habitat loss. A fifth of mammals, 30 percent of amphibians, 12 percent of known birds, and more than a quarter of reef-building corals face extinction, according to the "Red List" of threatened species.

- ENERGY: World energy consumption rose by 5.6 percent in 2010 and is set to double by 2030. Fossil fuels account for more than 80 percent of the energy supply, followed by renewables with around 13 percent, of which biofuels is by far the biggest contributor. In rural Africa, 85 percent of the population relies on biomass for energy.

- DEPLETED RESOURCES: Between 2000 and 2010, 13 million hectares (32.5 million acres) of forests disappeared each year, accounting for the third biggest single source of greenhouse gas. Fish catches increased fivefold between 1950 and 2005. Thirty percent of fisheries are over-exploited, depleted or recovering from depletion. By 2050, the world will produce 13.1 billion tonnes of waste annually, a fifth more than today.

- FOOD: One person in seven suffers from malnourishment. Demand for food will increase by some 70 percent by 2050, which will lead to a nearly 20 percent increase in global agricultural water consumption. Between 2000 and 2010, 203 million hectares (500 million acres) of land were transferred to foreign control, especially to China, petro-economies in the Gulf and rich countries eager for food security and biofuels. Two-thirds of the transactions were in Africa and 14 percent in Asia.

- TAXES AND SUBSIDIES: Subsidies for fossil fuels amounted to $312 billion in 2009. A tax of 0.005 percent on foreign exchange trading could raise $40 billion a year in additional aid for poor countries, which in 2010 stood at $130 billion.

SOURCES:

- Population: The State of World Population 2011, published by the United Nations Population Fund (UNFPA); UN Environment Programme (UNEP) 2012 report, 'Green Economy in a Blue World'

- Ecological footprint: Global Footprint Network website

- Poverty: World Bank report, February 2012; 2011 Human Development Report by the UN Development Programme (UNDP); UN's Fourth World Water Development Report

- Climate change: Carbon estimate in letter to science journal Nature Climate Change, December 2011; Intergovernmental Panel on Climate Change (IPCC) 2007 Fourth Assessment Report; May 2012 estimate on carbon pledges by Ecofys and Climate Analytics; Global Footprint Network

- Energy: BP Statistical Review of World Energy 2011; UNEP; 2011 report by Organisation for Economic Cooperation and Development (OECD) and International Energy Agency (IEA)

- Depleted resources: UNEP

- Biodiversity: "Red List" of International Union for Conservation of Nature (IUCN)

- Food: UN's Fourth World Water Development Report; Land Matrix Project

- Taxes and subsidies: UNDP's 2011 Human Development Report