There isn't enough arable land and fresh water to meaningfully address climate change in the time necessary. Algae farming with sea water might be a good alternative if we could address disposing the the algae without emissions.
This is the critical flaw in betting mostly on trees to remove CO2 from the atmosphere.
To get to the now-unlikely target of +1.5°C by 2100, the need is on the order of 6 billion tons of CO2 to remove each year by 2050[1]. A mature tree can capture only around 22 kg a year[2], so removing 6 billion tons would require planting 270 billion trees each year. To get a sense of the magnitude of the effort, there are an estimated 3 trillion trees on Earth today; we'd need to plant just as many in only 11 years.
