2025 marks a crucial tipping point in the world’s fight against climate change.

At the 2015 United Nations (UN) Climate Change Conference in Paris, 196 countries entered a legally binding treaty known as the Paris Agreement. 

The treaty calls on its signatories to take climate action in their respective nations to prevent the average global temperature from rising to catastrophic levels before 2050. The Paris Agreement defines this as an increase in global temperature of 2°C above pre-industrial levels (the period between 1850 and 1900). This is the maximum allowable threshold — ideally, to mitigate the most damage, the average global temperature should not rise higher than 1.5°C above pre-industrial levels.

As 2025 begins, a crucial global turning point for climate action is at hand. In the Paris Agreement, 2025 is outlined as the year in which greenhouse gas emissions must peak for the world to have a chance at the 1.5°C threshold for climate change. Continuing increases in global emissions after this year would mean diminished chances of reaching this goal. 

What’s in Half a Degree?

If 2°C is supposed to be the maximum threshold the global average temperature can increase to, why should it matter that 2025 might be the last chance to reduce emissions enough to stay below 1.5°C?

The half-degree difference between these temperatures might seem insignificant — it would be difficult to notice a half-degree change in the weather during our daily lives. However, this change is far from trivial. 

A 2024 study in the journal Nature found that each 0.1°C increase in global average temperature above 1.5°C increases the likelihood of triggering climate tipping elements. Climate tipping elements (also known as climate tipping points) are thresholds that, when exceeded, can cause exponential changes in environmental systems. 

Examples of tipping elements that can profoundly affect the Earth include large ice sheets, oceanic and atmospheric circulation patterns, and large biosphere features such as the Amazon Rainforest and Boreal Permafrost. These elements are deeply interconnected with global ecological processes. While they can have stabilizing effects, they can also trigger cascading changes in a variety of systems when disturbed. The melting of the Greenland ice sheet, for example, could cause changes in Atlantic circulation, affecting precipitation levels in the Amazon. 

A few of Earth’s crucial tipping elements, such as coral reef die-off, are at risk of being pushed over the edge even around 1.5°C. However, keeping warming to this level still greatly mitigates damage. Two degrees is considered the upper limit of warming beyond which many more tipping points will be set off, creating a cascade effect that threatens ecological and human health at a much larger scale.

In 2018, the UN’s Intergovernmental Panel on Climate Change released its Global Warming of 1.5°C special report, outlining the consequences of climate change at 1.5°C versus  2°C of warming. 

Some Notable Predictions? 

On a human level, two degrees of warming is projected to result in 37% of the global population being exposed to severe heat at least once every five years, compared with 14% at 1.5°C  of warming. Additionally, yields in fisheries and certain crops could experience a reduction in their harvests twice as severe as they would’ve experienced at a 1.5°C of warming.

In our ecosystems, a 2°C increase in global average temperature could result in double the amount of vertebrate and plant species and triple the number of insect species seeing at least a 50% reduction in their range, compared with projected numbers at the 1.5°C threshold.

What Are We on Track for Now?

The global average temperature hit a record high this year, and was the first year on record to hit an average temperature that exceeded the 1.5°C threshold compared with pre-industrial levels. It is important to note that this was bolstered by a strong El Niño event last year, which had a warming effect.

An October 2024 report from the UN predicts that, with current policies and pledges from member nations, the world is still on track for warming between 2.6°C and 3.1°C by the end of the century. The report indicated that emissions must be cut by 42% globally by 2030 to remain on track to limit warming to just 1.5°C. 

On the Positive Side…

Climate tipping elements don’t just have to be negative. There are also positive tipping points that, when triggered, create a positive feedback loop, reinforcing effective climate action. Investments in green energy, for example, might initially be hefty and have little yield, but overcoming the initial barriers allows development to accelerate rapidly and become cheaper until it reaches a tipping point where it is adopted at scale. 

Around 14% of the world’s primary energy (raw energy sources not yet converted by humans) comes from renewable technologies. While this number is still low compared to the amount of primary energy sourced from fossil fuels, new investments in green energy projects globally are estimated to be around 2 trillion USD annually, which is double the amount spent on all new fossil fuel projects. This investment, combined with the decreasing costs of renewables, is expected to lead to immense growth in global renewable capacity, projected to grow to 2.7 times its current capacity by 2030.

Other examples of positive climate tipping points include the increasing production of green ammonia (ammonia made through a carbon-free process) and the growing adoption of electric vehicles. In 2024, Norway became the first nation to have more electric vehicles on the road than standard gasoline-powered vehicles. In 2025, the country aims to limit the market to zero-emission vehicles, meaning all new car sales will be electric or hydrogen-powered.

While it might not appear that countries and their policies are on track in certain areas right now, slow changes in many spaces can suddenly lead to tipping points of exponential change. It is important to cause these positive tipping elements to tip sooner rather than later. 

One of the most effective ways to trigger positive climate tipping elements is through public policy, whether by subsidies, restrictions, or other measures. The Canadian federal election will take place on or before October 20 this year, meaning that all eligible voters have the opportunity to make their voices heard about preventing the global average temperature from rising above 2°C at some point during this critical year.