Limiting global warming to 1.5°C compared to 2°C reduces the severity of climate change impacts on our natural and human systems. As highlighted by the Intergovernmental Panel on Climate Change’s
(IPCC) Global Warming of 1.5°C special report, several hundred million people would be less exposed to climate-related risks to health, livelihoods, food security and water supply. For our natural systems, the IPCC projects that coral reefs will be virtually eliminated at 2°C, while under 1.5°C of warming, they will decline by 70-90%.
Human activities have already caused global warming of about 1.0°C and global warming is likely to reach 1.5°C around 2040 if it continues to increase at the current rate. While a 1.5°C world is still possible, we need to urgently and radically transform all systems at an unprecedented scale. Transforming the energy system will be crucial as unabated fossil fuels are currently responsible for over 80% of primary energy demand. We must move swiftly toward an increase in all available zero-carbon energy sources across all sectors.
As the global temperature increase is linked to cumulative net CO2 emissions, it is imperative that emissions remain within the carbon budget. This means that in parallel to aiming for net-zero emissions as early as possible in the second half of the century, we need to also achieve emissions reductions in the near-term to limit cumulative emissions. According to the IPCC, we need to reduce CO2 emissions by about 1.4 GtCO2 per year to limit warming to 1.5°C. It is therefore crucial that the transition to a zero-carbon energy system is accelerated now, using technologies already existing today.