The Paris Agreement indicates to hold the increase in the global average temperature to well below 2 ℃ above preindustrial levels and to pursue efforts to limit the temperature increase to 1.5 ℃ above pre-industrial levels to reduce the risk and impact of climate change. Then, the United Nations Framework Convention on Climate Change (UNFCCC)invite IPCC to provide a special report on impact and related pathways of greenhouse gases emissions for 1.5 ℃ global warming. Under 2 ℃ global warming, the risk of some types of extreme events will further increase; Some vulnerable systems, such as ecosystems and agricultural systems, will suffer more serious consequences. At the same time, the world will face more server consequences of sea surface level rise, coral reefs degradation and monsoon precipitation decrease. Regional responses to global warming with various magnitudes also show great differences. In general, limit temperature increase to 1.5 ℃ rather than 2 ℃ can further reduce risk of climate change. To understand 1.5 ℃ related issues more clearly, higher resolution models and more experiments specifically designed for 1.5 ℃ global warming are needed in order to quantitatively analyze its impacts on natural and human systems at global and regional scales.