This glacier in Greenland, the largest outside of Antarctica, is releasing enough ice daily to meet … [+] New York City’s water needs for an entire year.

NurPhoto via Getty Images

In 2024, global temperatures reached a record-breaking 1.55°C above pre-industrial levels. From deadly floods in South Asia to relentless wildfires across North America, the effects of a warming planet are becoming impossible to ignore. These events highlight the rapidly closing window we have to meet the Paris Agreement’s goal of limiting warming to well below 2°C above pre-industrial levels.

We are in a race against time and climate change. This article is your guide to the reasons for optimism and pessimism, and what must happen to achieve our climate goals.

Looking for more about our climate future, including exciting discussions on solutions and tipping points, check out my new The Big Questions podcast episode here.

Overview of the temperature target

2°C is the limit where climate science tells us that the risks to ecosystems, food security, and human health increase dramatically. While the Paris Agreement aimed to keep global temperature rise “well below 2°C” and pursue efforts to limit it to 1.5°C, the world has already reached 1.5°C, leaving little margin for error.

Staying below 2°C demands rapid and sustained emissions cuts. The remaining global carbon budget for 2°C is estimated at around 1,000 gigatons of CO2—about 20-25 years of emissions at current rates. Exceeding this limit increases the likelihood of climate tipping points, such as the collapse of the Greenland ice sheet or the thawing of methane-rich permafrost, which could drive further warming.

The case for optimism

Despite the daunting challenges of record temperatures and record emissions, there are compelling reasons to believe that staying below 2°C is achievable. Technological advances, shifting market dynamics, and new policy commitments provide causes for optimism.

Since 2010, the cost of solar power has dropped by over 90%, and wind power has followed a similar trajectory. Today, 80% of new electricity generation capacity is low-carbon, and innovations like advanced batteries and green hydrogen are scaling rapidly. Electrification can also vastly increase energy efficiency, for example, electric vehicles can be three-times more energy efficient than internal combustion engines. Green technologies are now creating alignment between economic competitiveness and decarbonization​​.

Global finance is also accelerating the low-carbon transition. Investment in clean energy now outpaces fossil fuel investments by more than 2-to-1. Meanwhile, nearly 90% of the world’s GDP is covered by net-zero commitments, reflecting the rising policy commitment to reduce emissions.

These trends demonstrate that we have the tools we need to decarbonize. We just need to deploy them faster.

The case for pessimism

While progress has been made, many argue that staying below 2°C is increasingly unrealistic given the scale of the challenges. Emissions are at record levels and rising.

The political and economic obstacles to decarbonization are significant. Even for nations with net-zero commitments, many lack enforcement mechanisms. Emerging markets, which are still rapidly industrializing, face unique challenges in reducing emissions while supporting economic development. Globally, fossil fuels still account for around 80% of primary energy consumption.

The risk of overshoot—exceeding the temperature limit before returning to it later in the century—compounds the difficulty. Recovering from temperature overshoot demands a massive scale up in carbon removal technologies that are still expensive, energy-intensive, or unproven at the necessary scale. For example, many carbon capture and storage (CCS) technologies remain far from commercial viability.

Tipping points present another risk. The thawing of methane-rich permafrost or the collapse of critical systems like the Atlantic Ocean currents could accelerate warming and other climate impacts beyond human control.

Overall view

Climate change is one of humanity’s defining challenges. On the positive, renewable energy has reached unprecedented levels of affordability, investment in clean energy is outpacing fossil fuels, and innovations in green technologies provide hope for a decarbonized future. However, emissions remain stubbornly high, tipping points loom closer, and the world’s reliance on fossil fuels continues to delay the transition.

Whether we can stay below 2°C will depends on our collective efforts. Governments must enforce stricter policies to meet their commitments, while financial markets and businesses need to accelerate investment in low-carbon technologies.

The next five years will be critical. With the remaining carbon budget rapidly shrinking, decisive action must replace incremental progress. Achieving this target will not only prevent the worst impacts of climate change but will also unlock a cleaner, more sustainable future for all.