Hopes for a new global deal to conserve life on earth received a much-needed boost today with the announcement of $2bn (£1.2bn) in funds from Japan and signs that negotiators are narrowing their differences at the United Nations conference on biodiversity in Nagoya.

Delegates said 15 of the 20 conservation targets in a draft strategic plan to ease the loss of habitat and species have been agreed, up from eight just 24 hours before. The moves mark a considerable acceleration after the grindingly slow progress of the past 10 days.

Britain added to the momentum by earmarking £100m for forest protection, but delegates tempered their optimism with warnings that the biggest political hurdles have yet to be crossed and there are only two full days left until the end of the meeting.

Environment ministers from 193 countries have gathered in Nagoya to draw up a protocol that will have three main strands: a strategic plan for global conservation, an arrangement for funding and monitoring, and a system for regulating and sharing the benefits of genetic resources.

Finance – a major stumbling block until now – was said to have nudged slightly closer to a resolution today amid growing signs of flexibility. The host nation pledged $2bn over three years to developing countries for the management of ecosystem management and sustainable resource use. This headline figure represented an almost tenfold increase on its previous biodiversity outlays, but it was unclear how much of this was fresh money and how much diverted from other areas of the aid budget.

Brazil – an influential, ecologically rich, developing nation – has called on the European Union to lift its funding commitments. The two have tussled repeatedly on this issue, but their language in the past 24 hours has been notably softer. "We are in contact with Europe on this and we see that there is a will to move in that direction," said Braulio Dias, secretary for biodiversity and forests in Brazil's Environment Ministry. "It is a difficult discussion but there has been progress."

The UK today committed £100m to international forestry projects that address the problems of habitat destruction and the loss of plants and animals.

The money, channelled through the Department for Environment, Food and Rural Affairs, comes from the £2.9bn international climate finance budget – one of the few areas of the budget that was increased in the Comprehensive Spending Review.

Elsewhere in the EU, governments with shaky budgets – Greece, Ireland, Portugal and Spain – have been reluctant for the bloc to commit additional funds beyond the roughly €1bn a year that it has spent on biodiversity since 2002.

However Janez Potocnik , european commissioner for the environment said extra financial support would be available if a sufficiently ambitious and achievable action plan is put in place. "You can expect more from Europe in the future," he said. "Some members states are pleading poverty. But there is a move to do more. Great Britain sets an example. If they can do it after cutting the budget by 30%, then you can see we are serious about dealing with biodiversity."

The UK environment secretary, Caroline Spelman, told BBC Radio 4's Today programme:"There is a strong political will among my colleagues, especially among EU countries, that we want to try and get an agreement."

"I think we can get agreement in some areas. If things are going well, we might get agreement in all of the areas."

However, wide differences remain on the most important goal of the conference: the establishment of a strategic conservation plan for the coming decade. The EU's aim of halting biodiversity loss by 2020 is being blocked by Brazil, which says a more realistic target is to reduce biodiversity loss to at least 50% and, where feasible, zero.

Similarly, efforts to expand protected marine areas to 15% of oceans are being blocked by India and China. The ministers of these two fast developing nations do not arrive until the final days, which has narrowed the time for a compromise.

Even if these problems can be resolved, the overall package could still fall through if no agreement is reached on the third strand, which aims to prevent biopiracy and establish rules for accessing genetic resources and sharing their benefits with local people. This topic remains entangled due to legal wranglings and conflicts between the views of environmental ministries and the commercial interests of big pharmaceutical companies.

"Overall, today was a very positive day. Japan's investment seems to have injected a lot of enthusiasm into the negotiations and now a final agreement is looking more likely," said Russell Mittermeier, president of Conservation International." We were already optimistic, but the $2bn exceeded our expectations. We are happy to see the host country of this meeting dedicate so much money and commitment to moving things forward."