Have we made any difference to climate change yet?

Quite possibly – but not in a good way. The principal drivers of climate change are greenhouse gases that trap the Sun’s heat. The most important of these is carbon dioxide (CO2), produced by human activities such as energy generation and transportation. The good news is that 2014 saw CO2 emissions from the energy sector remain static, suggesting the message about fossil fuels is finally getting through. The less good news is that in May the total amount of atmospheric CO2 exceeded the highest level recorded since scientific measurements began in 1958. Perhaps most concerning of all is the fact that even if emissions of all greenhouse gases ceased entirely tomorrow, any warming would still persist for many centuries. That’s partly because CO2 lingers in the atmosphere for several centuries after release, and partly because the oceans are slow to respond to global warming but are also just as sluggish to react to any cooling.