Despite urgent warnings over the need to curb greenhouse gases to avoid “dangerous” climate change, emissions are estimated to be rising by 2.5% this year, to a record 40bn tonnes.
Experts said at current rates the “quota” for the total amount of carbon dioxide that can be released into the atmosphere without pushing the world beyond 2C of warming could be used up within 30 years.
To keep temperatures from rising by more than 2C above pre-industriallevels, beyond which the worst impacts of climate change will be felt, over half the world’s fossil fuel reserves may need to be left in the ground, they said.
Emissions, which are primarily caused by burning fossil fuels, will have todecline by more than 5% a year to give the world a 50/50 chance of keepingtemperature rises below the 2C threshold.
The stark warning that time is running out to tackle spiralling greenhouse gasemissions comes ahead of a UN summit in New York this week to drive action inthe run-up to talks in Paris next year, where it is hoped a global climate dealcan be secured.
Corinne Le Quere, director of the Tyndall Centre at the University of East Anglia, said: “The human influence on climate change is clear.
“We need substantial and sustained reductions in CO2 emissions from burning fossil fuels if we are to limit global climate change.
“We are nowhere near the commitments necessary to stay below 2C of climatechange, a level that will already be challenging to manage for most countriesaround the world, even for rich nations. Politicians meeting in New York need to think very carefully about their diminishing choices exposed by climate science.”
Prof Le Quere is one of a team of scientists from the Global Carbon Project, which has published the “global carbon budget” analysis with a prediction for emissions in 2014 as well as an assessment for carbon dioxide output in 2013.
This year’s increase to 40bn tonnes puts current global annual emissionstwo-thirds (65%) above 1990 levels, the year against which attempts to cutgreenhouse gases are commonly measured.
Historic and future carbon dioxide emissions must remain below 3,200bn tonnes to make it likely temperature rises do not exceed 2C, the expertssaid, but 2,000bn tonnes of the quota had already been used up. The rest could be used up in 30 years.
China, the US, the EU, and India are the world’s largest emitters and between them account for 58% of global carbon emissions and four-fifths of the growth in carbon output in 2013, the annual analysis said. Globally emissions are expected to rise at a higher rate in 2014 than in 2013, when carbon dioxide output rose 2.3%.
Prof Pierre Friedlingstein of the University of Exeter said: “The implication of no immediate action is worrying clear, either we take a collective responsibility to make a difference, and soon, or it will be too late.”