The UN biodiversity meeting in Japan has agreed a 10-year plan aimed at preserving nature.
Targets for protecting areas of land and sea were weaker than conservation scientists wanted, as was the overall target for slowing biodiversity loss.
Most developing countries were pleased with measures aimed at ensuring they get a share in profits from products made from plants and other organisms.
Nations have two years to draw up plans for funding the plan.
"This agreement reaffirms the fundamental need to conserve nature as the very foundation of our economy and our society," said Jim Leape, director-general of WWF International.
"Governments have sent a strong message that protecting the health of the planet has a place in international politics, and countries are ready to join forces to save life on Earth."
The meeting settled on targets of protecting 17% of the world's land surface, and 10% of the oceans, by 2020.
These are regarded as too small by many conservation scientists, who point out that about 13% of the land is already protected - while the existing target for oceans is already 10%.
Many poorer countries say they do not have the resources to implement such targets.
"The forest and the other biological resources we have serve the general interests of the global environment," said Johansen Voker from Liberia's Environmental Protection Agency.
"So we expect assistance to be able to effectively conserve our environment for the common good of the world community."
Developed nations agreed to establish mechanisms for raising finance to help them - which could amount to hundreds of billions of dollars per year by 2020.
They are required to have a plan to raise such sums in place by 2012, when Brazil will host the second Earth Summit in Rio de Janeiro.
The sums might appear astronomical - particularly when you recall that governments are already committed to raising $100bn (£125bn) per year for climate change by 2020 - but French Ecology Minister Chantal Jouanno said it was not impossible.
"If you think that to solve the problem of biodiversity only public funds can be sufficient, it's just a dream, because the amounts necessary are so huge," she told BBC News.
"It needs to be private funds too - and not only voluntary private funds but... binding funds [from business].
"You are making profits from the use of biodiversity; so it's logical and it's legitimate that those profits return to biodiversity."
The trickiest issue - the agreement on sharing profits from the development of products drawing on genetic resources in developing countries, known as Access and Benefit-Sharing (ABS) - was resolved after developed nations, led by the EU, made some crucial concessions.
In particular, they agreed that the measures should cover anything made from this genetic material, technically known as "derivatives".
They had previouslty argued for a much narrower scope.
'More work needed'
Conservation groups warned that the agreement as it stands does not guarantee the erosion of species and ecosystems will be stopped.
"Participants may be leaving Nagoya, but they still need to be working to save life on this planet from Monday morning," said Jane Smart, head of the species programme at the International Union for the Conservation of Nature (IUCN).
"We need to harness the energy of this meeting, where we've seen huge and significant commitments in terms of reinvigorated political will as well as real money from the likes of Japan, and in terms of pledges to increase protected areas from the likes of Guinea Bissau."
Japan looks set to emerge with credit, having steered the tough negotiations through its final hours.
"What the Japanese government really wants to do here is to get agreement so they can be proud of the Nagoya CBD," said Wakao Hanaoka, oceans campaigner with Greenpeace Japan.
"What is really needed, since the Japanese government has just started its role of chairing the CBC until 2012, is to keep doing what they have promised to international society."
This meant, he suggested, taking effective conservation in the marine environment - including backing cuts in fisheries for threatened but lucrative fish such as bluefin tuna.