The first week of the U.N. climate talks in Paris, or COP21, has culminated in delegates coming to an agreement on the draft text of the international climate agreement, a 48-page blueprint that ministers will review and hopefully finalize into a comprehensive agreement by the time the conference ends on December 11.

The final agreement, they hope, will keep the increase in the Earth's surface temperature to a maximum of 2° Celsius, the level the scientific community believes must not be crossed in order to avoid the worst impacts of climate change.

BBC News environment correspondent Mark McGrath reported that many of the delegates were "relieved that they had at least reached this point, as it marks a critical point after four years of negotiations."

Following the draft's adoption, South Africa's negotiator Nozipho Mxakato-Diseko, speaking on behalf of more than 130 developing nations, said, "In the words of Nelson Mandela, it always seems impossible until it is done." His statement was received with loud applause.

"Nothing has been decided and nothing will be left behind," said French climate ambassador Laurence Tubiana. "This text marks the will of all to reach an agreement." But, she warned, "We are not at the end of the route. Major political issues are yet to be resolved."

The document, which offers ministers several options regarding the agreement's ultimate long-term goal, is still far from what must be accomplished at the landmark summit. Several critical issues remain. First, delegates have not agreed on the scale or timeline of reducing greenhouse gas emissions, which trap the sun's heat on the earth's surface, thereby increasing the global mean temperature. Second, it is unclear which nations should shoulder the brunt of the reductions. And third, it remains unclear how the changes recommended by the agreement will be financed and which nations should pay.

"We now need to summon the political will needed to make the hard decisions required for an effective and durable agreement that protects the most vulnerable among us," said Thoriq Ibrahim of the Maldives, who is chair of the Alliance of Small Island States.

Analysts said the key to the agreement is a quinquennial (or five-year) review that allows for nations to strengthen their commitments; what has been called a “ratcheting-up mechanism.” But for the plan to work, the world must move toward a low-carbon economy. For poorer nations, that means money to finance the costly shift to renewable energy technologies and help deal with ongoing impacts of a warming world, such as heat waves, droughts, floods, wildfires, extreme weather, rising sea level, ocean acidification and biodiversity loss. These climate-related effects are causing sudden shifts in local economies and food security across the world, including agriculture, subsistence farming and fishing.

Under the planned Paris accord, rich nations would be required to move hundreds of billions of dollars to developing nations by 2020.

"Perhaps this is the most exciting time in human history," said actor and environmentalist Sean Penn at a special event at the conference. "Those illusions of having too many difficult choices have always created chaos. Now we live in a time where there are no choices. We have certainty. The days of dreams have given way to the days of doing."

Penn has been working with French environment minister Segolene Royal to restore Haiti, with France funding the actor's major new environmental initiative, Haiti Takes Root, which aims to help the island following the 2010 earthquake, improve soil quality and promote sustainable forestry and renewable energy. After visiting with Royal in Paris in October, Penn said he was optimistic about COP21. But while negotiators remain confident they can avoid the failure of the 2009 U.N. climate talks in Copenhagen, there has been strong criticism of the new draft document, particularly its bias toward rich nations.

Tamar Lawrence-Samuel, associate research director at Corporate Accountability International, a Boston-based non-profit working to end abuse by transnational corporations, said the following in an emailed statement:

While the draft outcome released this morning for negotiation next week will likely be met with applause by Global North governments and their corporate board room backers, it fails to deliver meaningfully toward the systemic transition climate change requires. At the core of this failure are the obstinate negotiating positions of the U.S. and other Global North governments who are bent on deregulating the global rules applying to them and advancing the financial needs of big business over the survival needs of people.

And, despite the image of hope and action President Obama and other leaders painted on Monday, the chasm between rhetoric and action continues to grow. Whether it’s finance or technology, loss and damage or differentiation, the positions reflected in this text are heavily biased towards the U.S., Japan, EU and other Global North countries, and the emissions-intensive industries they represent.

The U.S. position, for example, reflects the strong limits placed on U.S. climate action by a Congress overrun by the unconstrained campaign spending of Koch Industries, Exxon Mobil and other big polluters. As a result, President Obama has said the United States can’t accept a legally binding agreement and is failing to come forward with any new commitments on important issues like finance, technology and capacity.

Rather than advancing the interests of polluters through a weaker climate policy regime this agreement must recognize the historical responsibility of the Global North, provide justice for the Global South and catalyze the rapid transition away from dirty energy. The primary obstacle to these and other policy imperatives is to insulate the policymaking process from the corrosive influence of big polluters, both here at the UNFCCC and at home in national governments. Only then will climate policy truly value people over profits.

Poorer nations, particularly low-lying coastal and island nations that are most at risk for becoming submerged under a rising sea level, prefer the agreement to embrace the much more difficult target of 1.5° Celsius. That target would require the global economy to become fully powered by renewable energy sources by 2050. A study by the U.S. Department of Energy’s National Renewable Energy Laboratory found that the U.S. can generate 80 percent of its electricity from renewable energy by 2050, using available technology. But that remains a fantasy as long as renewable energy continues to be economically disadvantaged in favor of fossil fuel: In 2013, according to the International Institute for Sustainable Development, consumer subsidies to fossil fuels totaled $548 billion, compared to only $121 billion for renewables.

Worryingly, COP21 is hampered by an unprecedented level of corporate sponsorship. “Inviting some of the world’s biggest polluters to pay for the COP is akin to hiring a fox to guard a hen house,” said Patti Lynn, executive director of Corporate Accountability International. “We must eliminate this conflict of interest before COPs become corporate trade shows for false market-based solutions.”

The World Wide Fund for Nature, an international non-governmental organization promoting conservation and biodiversity, stresses that climate change "will impact some of the world's poorest and most vulnerable people, disrupting food production, and threatening vitally important species, habitats and ecosystems."

But as long as the rich nations—and their big polluters—dictate the terms of the Paris accord, maintain unhealthy fossil fuel subsidies and refuse to establish a long-term market for renewable energy that includes putting a price on carbon emissions, a world that protects more vulnerable nations, humans, animals and plants from the impacts of climate change will remain a dream. The science is clear: Unchecked climate change will be devastating for humanity and our fellow species. Two weeks of meetings seems hardly enough time to achieve a meaningful climate agreement with actionable goals that are legally binding. It is highly unlikely that the final accord will please everybody. Hopefully, at the very least, it will move the needle in the right direction.

Tasneem Essop, former provincial minister of environment for Western Cape, South Africa, who is now working on WWF’s Global Climate Deal Network Initiative, said, "We're hoping that in the rush to the end, ministers do not trade ambition for expediency, and remain true to the science."