Podcast Summary
Carbon Dioxide and Plant Growth: Satellite data shows an increase in vegetation growth in semi-arid areas due to carbon dioxide emissions, but the overall impact on the environment is still a subject of debate and ongoing research
There is ongoing debate about the impact of carbon dioxide emissions on the planet, particularly in relation to climate change. Some argue that the increase in carbon dioxide has led to unexpected positive effects, such as an increase in plant growth, particularly in semi-arid areas. This increase in plant growth can be observed from space using satellite data, which measures the amount of light reflected by different parts of the Earth. Dr. Chi Chen, a researcher at Rutgers University, explained that vegetation absorbs certain wavelengths of light during photosynthesis, and these wavelengths overlap with visible light. By analyzing satellite data in different wavelengths, researchers have observed an increase in vegetation growth over the past 20 years, particularly in areas that were previously expected to become deserts due to climate change. However, it's important to note that this is just one perspective on the issue, and there are also valid concerns about the negative impacts of carbon dioxide emissions on the environment. Ultimately, the complex relationship between carbon dioxide emissions, climate change, and plant growth requires ongoing research and careful consideration.
Earth's leaf area index: One-third of the world's vegetated area showed an increase in leaves while two-fifths saw a decrease, resulting in a net greening of approximately 2.3% per decade, equivalent to about 5.4 million square kilometers of new leaf area over an 18-year period
Satellite data measuring the absorption of light by plants has allowed scientists to estimate the Earth's leaf area index, indicating how much vegetation exists and how it's changing. A study from 2019 found that one-third of the world's vegetated area showed an increase in leaves, while two-fifths saw a decrease, resulting in a net greening of approximately 2.3% per decade. This equates to about 5.4 million square kilometers of new leaf area over an 18-year period. While Jordan Peterson's statement of a 20% increase in greening over 20 years may be roughly in the same ballpark, the specific numbers differ. The overall trend, however, is that the Earth is experiencing a net greening effect.
Global Greening Rate: The global greening rate is around 4.6% for a 20-year period, primarily driven by CO2 fertilization, but it doesn't negate the ongoing issue of climate change
The world has been getting greener, but the change is much less than the 20% suggested by Jordan Peterson. According to recent studies, the global greening rate should be around 4.6% for a 20-year period. Some regions, like China, have shown more significant greening trends, with an increase of about 20% in leaf area over the past 20 years. This greening is due to a combination of factors, including deliberate tree planting and agricultural changes. However, the primary driver of this global greening trend is CO2 fertilization, which occurs when higher concentrations of CO2 in the atmosphere allow plants to grow more efficiently. While this trend is not insignificant, it's important to note that it doesn't negate the ongoing issue of climate change and the increasing concentration of greenhouse gases in the atmosphere.
CO2 enhancement of plant growth in wetter areas: CO2 enhancement of plant growth is most significant in wetter areas, not arid ones, contributing to carbon absorption but not fully offsetting human-induced emissions
The increase in CO2 levels, which contributes to climate change, also enhances plant growth in many regions, leading to a greener Earth. However, contrary to popular belief, the most significant greening is occurring in wetter areas, not arid ones. Plants benefit from the increased CO2 as it improves photosynthesis and reduces water loss, making them more resilient. This process contributes to the absorption of carbon from the atmosphere, helping to mitigate some of the human-induced carbon emissions, but it cannot fully offset them. Despite Jordan Peterson's argument, the greening in arid regions is not the most substantial.
Carbon emissions ecological consequences: Carbon emissions contribute to climate change, extreme weather events, rising sea levels, negative impacts on vegetation growth, and potential food insecurities, particularly in tropical regions.
Carbon emissions have far-reaching ecological consequences beyond just contributing to climate change. These consequences include increased risks of extreme weather events, rising sea levels, and negative impacts on vegetation growth, particularly in tropical regions. The Intergovernmental Panel on Climate Change warns that if global warming reaches two or three degrees, negative impacts on crop yield could lead to major food insecurities. While warming may benefit vegetation growth in colder regions, it can introduce more heat stress or drought stress in tropical regions. It's important to consider all of these factors when assessing the net ecological impact of carbon emissions. And if you're interested in learning more about the history of economics, tune in to Planet Money Summer School every Wednesday on the Planet Money podcast from NPR.