We may look back on the years 2009 to 2019 as the lost decade a time when the world awoke to the reality of climate change only to squander the chance to take the action needed to tackle it. Now, many scientists fear the targets required to avoid catastrophe are slipping out of reach.

On Dec. 15, politicians from 194 countries wrapped up the 25th United Nations climate conference in Madrid. But in an outcome youth activists have described as another year of failure, the only thing nations seemed to agree on was that theres an urgent need to act.

Never have I seen such a disconnect between what the science requires and what the climate negotiations are delivering in terms of meaningful action, said Alden Meyer, strategy chief at the Union of Concerned Scientists. For 25 years, the world has been trying to figure out how to tackle fossil fueled-global warming. And now its a crisis.

As this decade likely the hottest on record comes to a close and another begins, one glaring question is: Can the world make up for this lost time? Thousands of scientists recently declared a climate emergency , and the U.N. has given the world just over a decade to act. With the clock ticking closer to midnight, its worth reflecting on how we got here and what we might learn from the past 10 years.

From Copenhagen To Paris

Hopes were sky-high in advance of the 2009 annual climate conference in Copenhagen. It was supposed to be the moment the international community started taking climate change seriously and pledging real action. That December, a record 110 heads of state, along with thousands of activists, scientists, business leaders, celebrities and indigenous people, flew to Denmarks snowy capital expecting to see the U.N. broker an historic climate deal to stabilize fast-rising emissions.

The science was robust; the public wanted it; and governments had, at least publicly, agreed that strong action should be taken. But huge expectations quickly turned to collective failure.

After two weeks of discussions, schisms widened between rich and poor countries and the talks broke up in scenes of chaos and recrimination; the grand plan to get all countries to agree to halve overall greenhouse gas emissions by 2050 and to hold global warming to a maximum increase of 2 degrees Celsius (around 3.6 Fahrenheit) above pre-industrial temperatures flopped. And with that, the world went back to the drawing board.