Thirty countries represented pledged $9.3 billion (7.4 billion euros) for a fund to help developing countries cut emissions and prepare for global warming, German Environment Minister Gerd Müller said.
The South Korea-based fund aims to help developing nations invest in clean energy and green technology and build up defences against rising seas and worsening storms, floods and droughts.
It boosts countries least to blame for, but most at risk from, climate change with grants, loans and private capital for projects such as solar and wind farms, reforestation or building up coastal defences.
The Berlin pledging event allows the participating countries "to show leadership in tackling one of the greatest threats to humankind," said Hela Cheikhrouhou, the GCF's executive director.
UN climate chief Christiana Figueres had called for an initial capitalisation of at least $10 billion by the end of the year, to be disbursed over four years from 2015.
The fund was about three-quarters there before the Thursday gathering.
The United States days ago pledged $3 billion and Japan $1.5 billion, after Germany and France promised $1 billion each, and Sweden over $500 million.
Smaller amounts totalling less than $1 billion between them have been offered by Switzerland, South Korea, the Netherlands, Denmark, Norway, Mexico, Luxembourg and the Czech Republic.
Britain pledged around $1 billion on Thursday.
Melting ice, extreme weather
The fund is seen as a step toward a far more ambitious goal set at the Copenhagen climate summit five years ago -- for rich nations to "mobilise" $100 billion a year for broader climate finance by 2020.
UN climate experts have cautioned there is no time to lose in the battle against global warming, which the world body's chief Ban Ki-moon last week labelled "the defining issue of our times".
The UN Intergovernmental Panel on Climate Change warned this month that time is running out to limit warming to two degrees Celsius (3.6 degrees Fahrenheit) by 2100 from pre-industrial levels.
They said Earth is on a likely trajectory for at least four degrees Celsius warming -- a recipe for melting ice caps, extreme weather events, habitat and species loss and conflict for resources.
After years that saw little progress in climate talks, the world's two biggest economies and top polluters, China and the United States, earlier this month agreed to new targets.
At a Beijing meeting, President Barack Obama committed the United States to reducing its greenhouse gas emissions by 26-28 percent by 2025 compared to two decades earlier.
China, the world's top polluter, agreed for the first time to slow emissions growth and ultimately reverse it after emissions peaking "around 2030".
The 28-nation European Union, the third-largest greenhouse gas producer, has pledged to cut its emissions by at least 40 percent by 2030 from 1990 levels.
The world's most powerful economies at a G20 meeting in Australia last weekend urged "strong and effective action" on climate change, including by financing the Green Climate Fund.