'Consternation in boardrooms'
Some environmentalists said the Paris agreement was a turning point, predicting the 1.5C goal would help to doom the fossil-fuel industry.
"That single number, and the new goal of net zero emissions by the second half of this century, will cause consternation in the boardrooms of coal companies and the palaces of oil-exporting states," Greenpeace International chief Kumi Naidoo said.
Developing nations had insisted rich countries must shoulder the lion's share of responsibility for tackling climate change as they emitted most of the greenhouse gases since the Industrial Revolution.
The United States and other rich nations countered that emerging giants must also do more, arguing developing countries now account for most of current emissions and thus will be largely responsible for future warming.
On the crucial financing issue, developed countries agreed to muster at least US$100 billion (92 billion euros) a year from 2020 to help developing nations.
However, following U.S. objections, it was not included in the legally binding section of the deal.
Ahead of the talks, most nations submitted voluntary plans to curb greenhouse-gas emissions from 2020, a process billed as an important platform for success.
But scientists say that, even if the pledges were fully honored, Earth will still be on track for warming far above safe limits.