<p>An increasing number of countries have committed to reach net-zero carbon emissions, usually between 2050-70. Any remaining emissions of carbon dioxide or other greenhouse gases would be cancelled out by increased forestry or other methods to remove atmospheric CO2.</p>

<p>What are realistic scenarios for reaching net-zero by mid-century? What are the key features of each? What are the conditions for them to be realised, and what are the environmental, technological, economic and political implications?</p>
