Greenhouse gas emissions from fossil fuel combustion and land use are changing the radiative budget of the Earth and changing its climate. The negative impacts of this climate change on natural and human systems are already emergent. The solution is to eliminate greenhouse gas emissions altogether as soon as possible, but the rate at which these emissions can decrease is limited by human reliance on fossil fuels for energy and the infrastructural, socio-economic, and behavioral inertia of current systems around the world. In this chapter, we discuss the physical impacts as well as the many challenges and obstacles to ‘bending the curve’, and provide a framework of possible solutions.