BARCELONA, SPAIN - The Green Climate Fund, one of the main sources of finance for developing nations to tackle climate change, is hoping wealthy countries will pledge between $9 billion and $10 billion to refill its coffers at a conference in Paris Friday.

Climate finance analysts said the outcome would be key to building trust with poorer states preparing more ambitious climate action plans, which are to be submitted to the United Nations by the end of 2020.

Environment and development groups are calling for at least $15 billion in new commitments for the Green Climate Fund (GCF), saying projects that may use up close to that amount are already in the pipeline, with needs only increasing as the planet warms.

A matter of survival

Lucile Dufour, international policy adviser with Climate Action Network France, said the GCF replenishment was happening "at a crucial point in the fight against climate change," and called on donors to double their contributions at a minimum.

"This is a matter of justice and survival for developing countries and the most vulnerable communities," she told journalists, noting the devastation from increasingly wild weather around the world.

The fund's executive director, Yannick Glemarec, told the Thomson Reuters Foundation that this week's meeting would be a "success" if pledges exceeded the $9.3 billion garnered at its first conference in 2014.

Since late last year the fund has secured pledges of about $7.4 billion from 16 countries for 2020-2023, with large donors like Germany, France and Britain doubling 2014 contributions.

New announcements from some other potentially large donors are expected to raise that figure Friday, including Japan, Italy, Switzerland, Finland and Belgium.

"It is not easy right now for any kind of financial contributors to dramatically increase their contribution because most of them are facing real budgetary constraints," Glemarec said, noting some "exceptional efforts" to double donations.

US won't deliver pledge

Despite total promises of just more than $10 billion for the fund's first five years, U.S. President Donald Trump, a climate-change sceptic, refused to deliver two-thirds of his country's $3 billion pledge.

Currency fluctuations meanwhile further cut the actual total available to the fund, to about $7.2 billion.

Glemarec and others expressed hope the United States could "re-engage" with the fund in coming years.

Joe Thwaites, a climate finance researcher with Washington-based World Resources Institute, said domestic politics meant it was "disappointing but not surprising" that the United States and Australia had indicated they would not contribute now.

He also urged some countries whose new pledges were flat or up slightly, like Canada and the Netherlands, to give more.

A report from the U.N. climate science panel showed last year that climate action financing, both from governments and business, had so far been inadequate, Thwaites said.

"There is a very clear sense that we need to see major increases and particularly for adaptation, where the needs are only going to rise."

More for the poorest?

The GCF has allocated about $5.2 billion to 111 projects in 99 countries ranging from green, low-cost housing in Mongolia's polluted capital and a rapid-transit bus system in Karachi using methane to restoring climate-threatened ecosystems in Namibia.

It expects to have parcelled out the rest of its initial pot by the end of 2019, Glemarec said, adding he hoped it would be able to grow its project pipeline in the future.

Aid agencies praise the fund's push to divide its money between projects to reduce planet-warming emissions and efforts to adapt to climate shifts and rising seas, as adaptation has received only about a fifth of global climate finance until now.

Glemarec said that since 2015 nearly 70% of the $1.9 billion the fund had allocated for adaptation was for projects in the most vulnerable poor countries, African nations and small island states, stressing the aim was to maintain or raise that share.

Liane Schalatek, associate director at the Heinrich Böll Foundation North America and civil society observer at the GCF, said it should increasingly work with approved ministries and agencies in developing states to reach local communities.

"There needs to be a focus on the poorest and most disenfranchised people who are usually not given voice and much opportunity to participate in or benefit from decision-making on climate change," she said.