Trees Will Not Save Us From Climate Change

Aaron Fisher | September 11, 2023

There is this magical view that forests and trees are going to save us from climate change. They will certainly be a part of the solution, but they are not going to be the whole solution. And it’s looking likely that they aren’t going to be nearly as large a part of the solution as originally thought.

Forests Emitting More CO₂ Than Absorbing

A new USDA report is showing that U.S. forests could worsen global warming instead of easing it because of natural disasters and aging.

Natural Disasters- The increasing frequency and severity of natural disasters: wildfires, drought, flooding, and tornadoes damages forests and reduces their ability to capture and store carbon.
Tree Age– Younger trees absorb more carbon per year than mature trees.

Currently 11% of U.S. carbon emissions (150 million metric tons) are absorbed by forest annually. By 2070, that number could be less than zero. Simply put planting more trees will not end the challenge of climate change. Source

How We Harvest Lumber Matters

Clearcut logging, where all of the trees are cut down, leads to significant problems with water pollution and flooding. Trees and ground cover leads to more snow on the ground, and more solar radiation reaching the snowpack. Without these, snow melts faster causing larger floods. Source

The challenge is that clearcut logging is the most economical way to harvest because you minimize equipment movement. Sustainable forestry is possible it will just require managing to more than simple economics.

The Paradox of More CO₂

While more CO2 being available in the atmosphere should lead to expedited photosynthesis, that is not what has been observed. Models have shown that photosynthesis rates have slowed globally since 2000. Researchers have found that is largely due to dryer air conditions as photosynthesis also requires water. Source

While there is not scientific agreement on this, this being at all true would greatly upset the value of increased plantings to offset the emissions of CO2 emissions driving global warming. Source

Forests Carbon Offsets: Less Than Promised

Carbon offset projects claiming to curb deforestation are significantly overestimating their impact. Source

- Study looked at 26 projects. Only 8 of those 26 showed any evidence of reducing deforestation, but none met their whole goal.
- Of the projected 89 million in carbon offsets sold, only 6.1% would be associated with actual carbon emissions reductions.

Simply put if we rely on financial tools and incentives for market-based solutions to address climate change, they need to be transparent and accountable. It seems the current system of forest carbon offsets is neither, which means we need to get better or look elsewhere if we are going to address this challenge.

The sources of much of this information are well respected journals like Science and government agencies invested in agriculture like the USDA. This does not comport well with the vision that plants will save us from global warming.

I put this forward not to say it’s not worthwhile to meet the challenge of global warming, but that we don’t have the luxury of ignoring data. We need to get this right, now and start looking beyond the trees.