I saw this as news today.<\/p>\n
https:\/\/www.unep.org\/news-and-stories\/press-release\/unep-world-set-cross-15degc-global-warming-can-still-limit-adapt-and<\/a><\/p>\n Here is my response. For those with an open mind not those who live in past sun centric flat earth realms.<\/p>\n I’ll search for information about the relationship between CO2 concentration and greenhouse plant growth, particularly regarding fruit size.\u00a0Based on the search results, here’s what research shows about CO\u2082 concentration and its effects on greenhouse plant growth and fruit size:<\/p>\n Ambient vs. Enriched Levels:<\/b><\/p>\n Yield Increases:<\/b><\/p>\n Fruit Characteristics:<\/b><\/p>\n Environmental Factors:<\/b><\/p>\n Saturation Point:<\/b><\/p>\n Quality Impacts:<\/b><\/p>\n The data clearly supports that controlled CO\u2082 enrichment in the 800-1,200 ppm range significantly improves both the size and quantity of fruits in greenhouse production, particularly for C3 crops like tomatoes and cucumbers.<\/p>\n <\/p>\n Based on the search results, here’s the comparison between greenhouse CO\u2082 levels and atmospheric concentrations:<\/p>\n Current Status (2024-2025):<\/b><\/p>\n 1,000-1,300 ppm in Greenhouses:<\/b><\/p>\n The relationship between CO\u2082 concentration and temperature is complex, but climate models provide these estimates:<\/p>\n Climate Sensitivity Framework:<\/b><\/p>\n Projections for 1,000 ppm:<\/b><\/p>\n Important Context:<\/b><\/p>\n Key Distinction:<\/b>\u00a0It’s crucial to understand that greenhouse CO\u2082 enrichment (1,000-1,300 ppm) is a localized, controlled environment<\/b> that doesn’t directly translate to global atmospheric conditions. The CO\u2082 in greenhouses is contained and used specifically for photosynthesis enhancement, while atmospheric CO\u2082 affects global climate systems through radiative forcing over the entire planet.<\/p>\n <\/p>\n Based on the search results, here’s what we know about maximum recorded CO\u2082 levels in Earth’s history:<\/p>\n Maximum from Ice Cores:<\/b><\/p>\n Key Finding:<\/b> Ice cores show that current levels (~430 ppm) are nearly 100 ppm higher than the highest levels<\/b> recorded in 2-million-year-old ice cores 6<\/a><\/p>\n For periods older than ice core records, scientists use proxy methods (fossilized shells, soil carbonates, leaf stomata):<\/p>\n Deep Time Maximums:<\/b><\/p>\n Last 66 Million Years:<\/b><\/p>\n Last 3 Million Years:<\/b><\/p>\n Time Period<\/p>\n<\/th>\n Method<\/p>\n<\/th>\n Max CO\u2082 (ppm)<\/p>\n<\/th>\n<\/tr>\n<\/thead>\n Last 800K-2M years<\/p>\n<\/td>\n Ice cores (direct)<\/p>\n<\/td>\n ~300<\/p>\n<\/td>\n<\/tr>\n 3 million years ago (Pliocene)<\/p>\n<\/td>\n Proxies<\/p>\n<\/td>\n ~400+<\/p>\n<\/td>\n<\/tr>\n 14 million years ago<\/p>\n<\/td>\n Proxies<\/p>\n<\/td>\n <430<\/p>\n<\/td>\n<\/tr>\n 50 million years ago (Eocene)<\/p>\n<\/td>\n Proxies<\/p>\n<\/td>\n ~1,000-1,500<\/p>\n<\/td>\n<\/tr>\n 60-52 million years ago<\/p>\n<\/td>\n Proxies<\/p>\n<\/td>\n >2,000<\/p>\n<\/td>\n<\/tr>\n 500 million years ago (Cambrian)<\/p>\n<\/td>\n Proxies<\/p>\n<\/td>\n 4,000-9,000<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n <\/p>\n Important Context:<\/b> While CO\u2082 has been much higher in Earth’s deep past, the rate of current increase<\/b> is unprecedented in geological records. Natural changes typically occurred over thousands to millions of years, while human-caused increases have happened in just ~150 years 14<\/a>.<\/p>\n <\/p>\n This is a crucial question that touches on the difference between botanical potential<\/b> (what plants can<\/i> do with CO\u2082) and ecological\/systemic stability<\/b> (what the Earth system can handle during rapid change).<\/p>\n While it is true that higher CO\u2082 can stimulate plant growth (the “greening” effect), scientists and economists worry about the rate of change<\/b> for several critical reasons that go beyond simple leaf surface area:<\/p>\n You previously asked about fruit size. Research shows that while plants grow faster<\/i> and larger<\/i> in high CO\u2082, they often become less nutritious<\/b>.<\/p>\nOptimal CO\u2082 Levels for Greenhouses<\/h2>\n
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Effects on Plant Growth and Fruit Size<\/h2>\n
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Important Considerations<\/h2>\n
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Current Atmospheric CO\u2082 Levels<\/h2>\n
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Comparison: Greenhouse vs. Atmosphere<\/h2>\n
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Global Temperature Increase Projections<\/h2>\n
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Ice Core Records (Direct Measurements)<\/h2>\n
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Geological\/Proxy Records (Indirect Estimates)<\/h2>\n
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Recent Geological History<\/h2>\n
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Summary<\/h2>\n
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\n \n\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n 1. The “Nutrient Dilution” Problem<\/h3>\n