The 2019 UN Emission Gap report indicates that global emissions must drop 7.6 percent per year from 2020 to 2030 for the 1.5°C goal and 2.7 percent per year for the 2°C goal.
The UN report says a 30 billion ton CO2 equivalent cut by 2030 is needed to reach the 1.5 degree target. However, the world is tracking to an 8.3 billion ton CO2 equivalent increase. The 2-degree celsius temperature target would need a 14 billion ton CO2 equivalent reduction from 2018 levels. There is a 38 billion ton CO2 gap for annual emissions between where we are going and where the UN report says we need to be for the 1.5 degree target and a 22 billion ton CO2 for annual global emissions by 2030. The world would need to cut about 4 billion tons of CO2 equivalent each year from 2020 to 2030 for the 1.5 degree target or 2 billion tons per year of CO2 equivalent each year from 2020 to 2030 for the 2.0 degree target.
Eliminating all emissions from the USA (6.2 billion tons per year), Canada (0.5 billion tons per year, Europe (3 billion tons per year) and Japan (1 billion tons per year) would be about half of the global emissions gap for the 2.0 degree target.
Globally eliminating all coal power usage would be about 10 billion tons per year. Germany has been trying and failing to eliminate its coal for energy usage by mainly building a lot of solar and wind power for the last thirty years. China and India are still building more coal power. China is at 13 billion tons of CO2e per year of annual emissions.
The world could offset the 38 billion tons of CO2 by planting 50 billion trees every year fr 20 years. If the trees were fast-growing trees that matured within ten years then this would offset about 41 billion tons of CO2. This would also need to be combined with preserving existing forests. Currently, the world has a net loss of trees and forests.
A new study of trees from the journal Science indicates that adding 1 trillion trees could store 200-830 billion tons of CO2. The world has room for 900 million hectares of trees. This would be over 1 trillion trees added to the existing 3 trillion trees. 5% of this would be about 50 billion trees per year.
The additional trees could be cut down in 20 years and the wood stores the CO2 unless they decay or are burned. Another batch of trees could be grown. If a breed of faster-growing trees are used then every 12-15 years a batch of a trillion trees would offset all of the CO2 produced by civilization.
The best (non-drone) tree restoration projects are restoring billions of trees at 30 cents a tree. This means 1 trillion trees would be $300 billion. Drone planting of trees can use 4000 drones, and 2000 people to plant 10 billion trees per year at about $1 billion per year.
Total global greenhouse gas (GHG) emissions, including from land-use change, reached a record high of 55.3 billion tons of CO2e in 2018. Fossil fuel CO2 emissions from energy use and industry, which dominate total GHG emissions, grew 2% in 2018, reaching a record 37.5 billion tons of CO2 CO2 per year.
“There is no sign of GHG emissions peaking in the next few years; every year of postponed peaking means that deeper and faster cuts will be required. By 2030, emissions would need to be 25% and 55% lower than in 2018 to put the world on the least-cost pathway to limiting global warming to below 2 degrees and 1.5 degrees, respectively,” the report says.