Warm in more than just a "look-out-the-window-it-is-41-degrees-today" kind of way. The final data for 2014 isn't in yet, but a provisional statement by the World Meteorological Organisation released to coincide with the UN climate conference in Lima, Peru last month said it was on track to be the hottest year on record, largely because the sea surface temperature across the planet broke previous records. About 93 per cent of the excess energy trapped in the atmosphere by greenhouse gases emitted by human activity ends up in oceans.

Across the planet, the average air temperature was about 0.1 degrees hotter than the average for the past decade and 0.6 degrees than for the average across the years 1961-1990.

The difference between the hottest years on record – 2010, 2005, 1998 and likely 2014 – is measured in hundredths of a degree. Meteorologists say this year is particularly noteworthy because temperatures were high despite there not being a full El Nino – the self-reinforcing loop where warm sea temperatures in the eastern Pacific combine with atmospheric pressure systems to make it hotter elsewhere.

Wherever 2014 ended up, the data suggests 14 of the 15 warmest years since the advent of modern thermometer records have been in this 15-year-old century.

Who is taking notice?

The Pope, for one.

Last May, the Vatican hosted a five-day summit to look at whether humanity's dealings with nature were sustainable. This year, Pope Francis reportedly plans to issue an encyclical on climate change and human ecology to parishioners across the globe. About 1.2 billion people identify as Catholic, more than two-thirds of them in the developing world.

The Pope's stance can be seen as part of his campaign to reduce poverty, and reflects that climate change is projected to hit the poorest people in the developing world much harder than the wealthy. This month, he is due to visit the Philippines, where he will meet survivors of Typhoon Haiyan, which killed more than 6000 people in November 2013. The extent of the Haiyan tragedy has been blamed on a toxic mix of extreme poverty and shoddy development in a climate hazard zone.

Pope Francis has raised climate change before, warning last year "If we destroy creation, creation will destroy us. Never forget this". How his stance sits with other senior figures within the church – Australian Cardinal George Pell, now overseeing the Vatican's finances as one of the Pope's most senior officials, likened acceptance of mainstream climate science to belief in mythology in a 2011 speech – is unclear.

No-one is suggesting this is a problem the Pope can solve, though. What about the world's leaders?

An Intergovernmental Panel on Climate Change synthesis report released in October – signed off by governments – recommended that fossil fuels be phased out by the end of the century. Although campaigners are increasingly pressuring institutions such as the Catholic Church to put their money where their rhetoric is and divest from fossil fuel companies, the principal focus in 2015 will fall on national governments.

The world's biggest two emitters – China and the US – surprised many by announcing a climate change agreement ahead of the G20 summit in Brisbane in November. The headline commitments (respectively, to stop their emissions rising by 2030, and to cut them by 26-28 per cent below 2005 levels by 2025) were seen by negotiators as significant first steps toward a post-2020 deal – and a signal that they were serious.

Along with European leaders, US President Barack Obama forced climate change on to the G20 agenda despite the reluctance of host Tony Abbott, raising expectations for the Lima summit.

So what was achieved at Lima – and what does it tell us about what to expect at the Paris conference?

Climate negotiations are to some extent an expectations game. If your benchmark for success is a deal that will immediately start cutting emissions at the pace and depth that scientists say is necessary, you're setting yourself up for heartbreak in the city of love come December.

Lima did not live up to the hype at the G20. Several decisions were delayed. But countries agreed to release more detailed commitments well before the Paris meeting. The hope is this will allow greater scrutiny and help reduce areas of disagreement at the summit.

Significant divisions remain, though. The relative responsibility of industrialised and industrialising countries to act remains a major point of contention. After heated argument, China and the world's poorest countries succeeded in keeping wording emphasising the distinction between developing and developed nations. But is China developed or developing, or somewhere in between? A recent study found its per capita emissions are now higher than Europe's, though nothing like those of the US or Australia. This dispute will rear its head again

The Lima talks also got caught up on whether the treaty would be "binding". Effectively, this is a debate over whether countries will agree to sign up to targets that are decided through negotiation as their fair share, and then inscribed in a treaty document. This was how it worked with the Kyoto Protocol – the 1997 treaty that covered developed countries, but was never ratified by the US, was abandoned without penalty by Canada, and which allowed Australia to continue increasing its emissions.

The idea that a treaty must be binding holds sway in Europe and parts of the developing world. Foreign Minister Julie Bishop went to Lima also demanding a binding treaty, but later softened her stance. It brought her into line with the US (which has no hope of getting a treaty ratified by Congress) and experts including Lord Nicholas Stern and Australia's Ross Garnaut. The alternative to a binding deal is each country making public commitments and promising to ramp them up over time. It is less exact, but is considered more likely to boost goodwill and lead to success.

Predictions are perilous, but the cautious expectation among observers is that, unlike the failure of Copenhagen, Paris will lead to a deal. But they expect it to be modest, and need to be built on over time.

Where does Australia stand?

Appearing before a British parliamentary committee last month, Prime Minister David Cameron was presented with the proposition that the Australian government was "in denial" about climate change, and a "backmarker" on the issue. He didn't disagree, but said: "I don't think they'll want to be. I think they will feel pressure and want to do more".

Senior members of the Australian government were in conflict over the issue late last year. Most notably, Ms Bishop was rebuffed when she asked the Prime Minister's Office to sign off on her even attending the Lima conference. She went to cabinet to get that decision overruled. Trade Minister Andrew Robb – a decisive voice in the debate when the Coalition abandoned support of carbon pricing and dumped Malcolm Turnbull as leader in favour of the sceptic Mr Abbott – was then sent to go with her.

Ms Bishop is widely considered an effective and forceful negotiator more sympathetic to achieving something meaningful on climate change than some of her colleagues, and her star within the government rose significantly last year. Where Mr Abbott had dismissed the Green Climate Fund to help poor countries cope, Ms Bishop went to Lima with a promise of $200 million, drawn from the existing foreign aid budget.

At a domestic policy level, Australia became the first country to abolish a charge on businesses that emit greenhouse gases. According to the World Bank, carbon pricing is either in place or being introduced in jurisdictions responsible for more than 22 per cent of emissions. Others are planning it. The success of the Coalition's replacement policy – primarily, a budget fund to pay for emissions cuts – will depend on a yet-to-be-designed "safeguard mechanism" to stop companies from increasing emissions. But experts strongly doubt enough money has been allocated to reach the promised minimum 5 per cent emissions cut by 2020.

The next big test for the government on the road to Paris will be the announcement emissions target for beyond 2020. The Climate Change Authority has already told us what it thinks: Australia should cut emissions by 19 per cent by 2020 and 40-60 per cent by 2030, partly through purchasing international carbon credits (which pay for cheap cuts in poor countries). The government's emissions reduction fund won't be enough to hit deeper targets after 2020 unless it is redesigned, or the government was to spend extravagantly. There is no appetite for the latter. How the government addresses this will be key to the climate debate in 2015.