Introduction

Sticking to the goals we set for ourselves can be hard. Ask anyone who’s set a New Year’s resolution. Have they reached their goal? Chances are the answer is no. Less than 10% of people who make resolutions achieve them. If we’re doomed to fail, are we better off setting no goals at all?

Not necessarily. Goals help shape our actions, so there’s benefit in working toward a goal, even if we don’t hit the exact target. It’s like playing darts—even if you don’t hit the bullseye, you still get points for being on the board.

Setting goals is an important part of addressing climate change. But if you look at the history of climate goals, humanity hasn’t hit a lot of bullseyes. In part, that’s because a problem as big as climate change requires global collaboration, which can be really difficult to achieve. Over time though, as the issue of climate change gained attention, more scientists and leaders from around the world got involved. They realized we needed something to help shape the planning, implementation, and evaluation of climate action. So they set some goals.

The Paris Agreement

In 2015, world leaders came together to form the Paris Agreement, one of the most significant international treaties addressing climate change. As a part of these negotiations, policymakers set a goal to limit global temperature rise to 1.5° Celsius, or about 2.7° Fahrenheit. The Paris Agreement was significant in part because 195 nations—nearly every country in the world—formally committed to the goal, unifying on a global scale what had previously been a mash-up of individual reduction targets and strategies.

The 1.5° Celsius (1.5°C) goal was also significant because it was one of the most ambitious targets ever set. Small, low-lying island nations like Kiribati and the Solomon Islands had long advocated for aggressive action toward climate change. That’s because these countries face some of the most immediate and dramatic threats from rising sea levels. So, a target like the Paris Agreement signed into international law represented a victory for those nations whose calls for serious action had been previously unanswered.

A little is a lot

But what’s the big deal about 1.5 degrees? Most people wouldn’t notice the difference between a few degrees on a sunny afternoon. But, in climate terms, a change of just a few degrees is significant. During the last ice age, the average temperature was just 6°C lower than today. And during the time of the dinosaurs, a time when the Earth was about 4°C warmer than today, you’d find palm trees in Antarctica.

To be clear, it’s not as if 1.5°C is a magical tipping point, below which everything is fine, and above which is a catastrophe. Instead, it’s the point along a scale of warming that many scientists have agreed we should strive to stay under to avoid the worst effects of global warming.

Striving for 1.5°C

In 2018, three years after the signing of the Paris Agreement, scientists released a special report. The report outlined the impacts of a 1.5°C temperature increase and the path the world would need to take to limit warming to that level. Specifically, the report called for global greenhouse gas emissions to reach “net zero” by 2050. “Net zero” refers to reducing greenhouse gas emissions as much as possible, and then capturing or removing those emissions that are unavoidable.

The report was shocking because it detailed the famines, drought, and extreme weather that were likely to come at even that small amount of warming. It was also shocking for its assertion about the speed at which we would need to make major changes— reaching net-zero emissions by 2050 would require a shift away from fossil fuels at an unprecedented rate. So unprecedented, in fact, that even in 2015, it seemed unlikely that we could achieve it.

Why set such an unattainable goal? Well, one reason is that the shocking nature of the report, released by an international panel of climate experts, caused people to pay attention. The report kicked off a wave of climate action at the political, corporate, and individual level that would have been unimaginable otherwise. Many of the major climate victories of the last few years—the plummeting cost of renewable energy and batteries, groundbreaking legislation like the Inflation Reduction Act—are thanks in part to the 1.5°C goal.

What comes after 1.5°C?

As of 2023, the Earth’s average global temperature had already risen about 1.1°C. While some scientists and policymakers believe that it’s still technically possible to reach the 1.5°C goal, many think that the reality of us actually getting there is pretty slim. That’s because while we have made significant progress since the Paris Agreement, emissions are still rising. And as long as we continue to use existing infrastructure like coal power plants for cheap energy, emissions are likely to continue to increase for many years.

But every tenth of a degree matters when it comes to limiting the impacts of rising temperatures. Extreme weather, for example, becomes even more extreme with every incremental increase in temperature. The upside of that is that even though we may not reach the 1.5°C goal, with every bit of warming we can avoid limits additional suffering from the impacts of climate change.

The 1.5°C goal has served an important function in unifying and motivating climate action. But as achieving 1.5°C becomes less and less likely, its usefulness is unclear. Some argue that a goal that’s likely out of reach becomes counterproductive, inspiring pessimism instead of optimism.

Is it time for countries and leaders to adopt a new strategy? Should we hold tight to the last bit of hope for 1.5°C? Or should we adopt a new organizing principle? The world looks different now than it did in 2015. Geopolitics, technology, and costs have changed significantly, and a one-size-fits-all goal might not be effective. At the international level, countries are experiencing different impacts of climate change, and countries have different histories of contributing emissions, and have varied resources to take on the problem. At the more local level, communities have a huge range of needs and priorities. Looking ahead, what are the targets we need—both ambitious and realistic—to inspire action into the next decade?