A comprehensive interactive analysis by Carbon Brief, synthesizing insights from nearly 70 peer-reviewed scientific studies, underscores the stark difference between a world warmed by 1.5°C versus 2°C. Although half a degree may seem small, the impacts of this difference are profound and far-reaching, affecting everything from sea levels to global food security and biodiversity.
Sea-Level Rise
One of the most visible and dangerous consequences of global warming is rising sea levels. At 1.5°C of warming, the world is projected to see an average sea-level rise of approximately 40 centimeters by 2100. However, if temperatures rise to 2°C, that number increases to 50 centimeters. While the 10cm difference may not appear drastic, it would expose an additional 10 million people to the risk of coastal flooding, storm surges, and habitat loss, particularly in low-lying island nations and densely populated coastal cities.
Water Scarcity
Water stress will also intensify. In regions such as the Mediterranean, water availability is projected to drop by 9% under 1.5°C warming, but that shortfall worsens to 17% under 2°C. This could have devastating consequences for agriculture, health, and livelihoods in already arid regions, potentially fueling migration and conflict over water resources.
Coral Reefs
The fate of coral reefs paints a tragic picture. Even at 1.5°C, an estimated 90% of global coral reefs are at risk of bleaching, a process that leads to their death. At 2°C, the risk jumps dramatically to 98%, essentially dooming almost all of the world’s reefs. These ecosystems not only harbor immense biodiversity but also protect coastlines and support fisheries and tourism-dependent economies.
Agriculture and Food Security
Food production is another area where the difference between 1.5°C and 2°C is stark. Under the higher warming scenario, crop yields are expected to decline more significantly, especially in tropical and subtropical regions. Staple crops like wheat, maize, and rice will suffer, potentially leading to widespread food insecurity and rising prices, with the most severe impacts felt by low-income and vulnerable communities.
Economic Impacts
From an economic standpoint, the poorest regions stand to lose the most. Countries in the tropics and Southern Hemisphere subtropics are projected to face disproportionate economic damage as warming rises. Limiting warming to 1.5°C could dramatically reduce global income inequality, as poorer countries would avoid the worst impacts of extreme heat, failed crops, and infrastructure damage.
The Urgency of 1.5°C
This extensive review clearly illustrates that limiting global warming to 1.5°C isn’t just preferable—it’s essential to reduce suffering, preserve ecosystems, and safeguard human development. While both 1.5°C and 2°C involve serious consequences, the half-degree difference could determine whether millions of people are displaced, ecosystems survive, and economies remain viable.
Ultimately, the Carbon Brief analysis serves as both a warning and a call to action: immediate, bold global efforts to reduce emissions and shift toward sustainable development can make the difference between manageable adaptation and irreversible catastrophe.
Source: Carbon Brief
