As world leaders convene December 2-13 for the United Nations Climate Change Conference in Madrid, Spain, Cal State Fullerton science faculty and student researchers are immersed in studies - impacts to land, sea and air- on climate change, a holistic term used to describe all components of the climate system, says Matthew E. Kirby, professor of geological sciences.

In a statement, the COP25 said its chief aim of the convention is to "raise overall ambition also by completing several key aspects with respect to the full operationalization of the Paris Climate Change Agreement".

These are both environmentalists and heads of state and government.

The opening ceremony began with a warning from Hoesung Lee, chair of the Intergovernmental Panel on Climate Change (IPCC): "If we continue as we are doing, we run the risk of increasing the temperature of the planet and that will have an effect and awful consequences for humanity and threaten our existence". Much of the focus this year will be on China, which burns half of the coal used globally each year, making it the world's biggest emitter of greenhouse gases. The climate conference was supposed to be held in Brazil, but that country dropped out under the then-newly elected president Jair Bolsonaro late past year, reports CNN News The summit was then moved to Chile.

In his opening speech to delegates, Guterres cited recent scientific data showing that levels of heat-trapping gases have hit a record high, reaching levels not seen for at least 3 million years when sea levels were 10-20 metres higher than today.

In a separate forum moments earlier, US House of Representatives Speaker Nancy Pelosi told the "COP25" conference that the world could still count on the US despite US President Donald Trump's decision to pull out of the Paris accord.

Leading the 15-strong Congressional delegation, Pelosi came to Madrid even as her colleagues in the House consider articles of impeachment against Trump.

To prevent temperatures from rising more than 1.5 degrees, the global economy must be carbon neutral by mid-century, a landmark United Nations report said past year.

"The most vulnerable atoll nations like my country already face death row" due to rising seas and devastating storm surges, she said.

Frank Pallone, sponsor of the 2050 bill, said there was "nothing inconsistent" about the two, as moving to renewable energy by 2030 would allow other sources of emissions, such as agriculture and some industries, to take longer to reduce.

Front-line negotiators describe COP25 as "technical talks" setting the stage for next year's meeting in Glasgow, where countries must confront the yawning gap between the Paris targets and current emissions.

"The global contributions to climate change fall far short", said Berthold Kuhn, an expert on sustainable development with the Free University of Berlin and senior advisor to the Dialogue of Civilizations Research Institute. The central motto of this 25th edition is 'Time for Action'.

Meanwhile, for all the considerable sustainability-friendly efforts from a tiny number of governments, including Morocco, the two-week Madrid summit comes as doubts continue about the concrete significance of big political events and on-paper commitments from world governments.

Cook Islands climate office director Wayne King said more than ever, the pressure was on for world leaders to do something.