Trees—Protectors against a Changing Climate

There are estimated to be about 3 trillion trees on Earth, or about half the number that existed before the dawn of human civilization. Trees are vital to at least four major biogeochemical cycles, namely, the carbon, water, nitrogen and oxygen cycles. In addition to absorbing carbon, and releasing oxygen through photosynthesis, trees are critical for maintaining biodiversity, providing habitat for 80% of land based wildlife, feeding the soil, generating clouds and increasing albedo (thus causing global cooling), influencing rainfall and weather patterns. The loss of trees, therefore, weakens our chances of reaching climate and biodiversity targets, and so proforestation and other practices to stringently preserve the functionality of and holistically restore forest ecosystems, must be adopted as a matter of urgency, paying due attention to soil, and species diversity including mycorrhizae; not being limited to insouciant “tree planting” solutions. Indeed, due to the tardiness of our actions to repair the Earth and its climate, severe restrictions to the cutting of mature trees must actually be enabled globally. However, this alone is not enough, and must be integrated with other forms of land, wetland, grassland and agricultural protection and restoration. Such Nature Based Solutions could provide over one-third of the climate mitigation needed by 2030 to keep within the 2 °C global heating limit. Nonetheless, it is also critical to curb greenhouse gas emissions at source, not only by implementing low-carbon, renewable energy, but also energy demand reduction strategies, such as insulating buildings, societal relocalisation, and local food growing.