If Liverpool scores fewer goals in one game, it doesn’t tell you much about its progress through the league.
The same goes for the planet’s climate.
2018 saw one of Britain’s hottest ever summers. California and the Arctic tundra saw wildfires burning out of control.
But today’s report from the Met Office concludes 2018 was the fourth warmest year on record.
But that doesn’t mean the world isn’t getting progressively warmer.
The three years warmer than 2018 were 2015, 2016 and 2017. And that is quite a trend. If the planet was in the premiership, it would be heading for glory.
The warming trend, and scientist’s increasing skill at modelling future climate, have also allowed the Met Office to predict something else this year. The next five years will all be a degree or more warmer than the “pre-industrial average”. In other words the world is predicted to be about one degree warmer than it used to be.
When, in 2015, the planet’s average surface temperature first exceeded the one degree milestone, it was a significant moment. Now it seems that moment is here to stay.
The decade from 2014 to 2023 is now predicted to be the warmest decade since historical records began. Perhaps not surprising, when it's well established that global warming is very much happening, but it makes it clear that the signal coming from our climate system is now showing clearly though the noise of year-on-year variations in the weather.
The Met Office’s report also finds that there is a ten percent chance that one of the next five years is 1.5 degrees warmer than the pre-industrial average. That’s the limit set by the Paris Climate Agreement beyond which the risks of climate change become dangerous for humanity. One year with average temperatures 1.5 degrees higher doesn’t mean we’ve reached that point. But it shows we’re stepping worryingly close to it.
The Met Office's analysis is a forecast, not a fact. But the trend of the last few decades is indisputable: the planet is getting progressively warmer. How much warmer it gets depends on us.