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Climate change is normal. it's caused by the sun.
Executive Summary
The claim that “climate change is normal” and “it’s caused by the Sun” mixes two distinct truths into a misleading conclusion: Earth’s climate has naturally varied over geological time, but the rapid warming observed since the mid-20th century is not explained by solar changes and is instead primarily linked to human-driven greenhouse gas increases [1] [2] [3]. Multiple observational records and climate-attribution studies show solar irradiance has not increased in the period of fastest warming, while atmospheric and surface patterns match greenhouse forcing rather than a stronger Sun [4] [5] [6].
1. Ancient climate swings are real — but they don’t explain today’s rapid warming
Paleoclimate records confirm that Earth’s climate has experienced large, natural changes over millions of years due to orbital cycles, volcanic events, and solar variability; natural variability is a documented background fact [1]. Those long-term drivers operated over centuries to millennia and produced temperature shifts consistent with slower forcings, not the abrupt, sustained rise in global average temperatures observed since the mid-20th century. Attribution studies that separate natural from human influences find that recent warming cannot be reproduced by natural drivers alone; models and observations show a dominant human fingerprint in the warming pattern and magnitude [2] [7]. This distinction matters because acknowledging past variability does not negate the evidence attributing current change to different agents.
2. The Sun’s output has been flat or declining during the warming surge
Direct satellite measurements of total solar irradiance since the late 1970s show no net increase that could account for the modern warming trend, and some datasets indicate a slight decline in recent decades [4] [6]. If the Sun were the primary cause of contemporary warming, warming would appear throughout the atmosphere; instead, observations show the lower atmosphere (troposphere) warming while the upper stratosphere cools — a pattern consistent with increased greenhouse gases trapping heat near the surface, not increased solar heating [4] [6]. Independent syntheses and government science summaries conclude solar variability plays only a small role in recent decades compared with anthropogenic forcings [8] [5].
3. Observational fingerprints point to greenhouse gases, not solar shifts
Satellite and balloon records reveal a troposphere warming and stratosphere cooling signature that matches the physics of increased greenhouse gas concentrations; solar-driven warming would warm the whole atmospheric column, including the stratosphere [4] [6]. Climate models that include only natural forcings (solar and volcanic) fail to reproduce the magnitude and rate of late-20th and early-21st century warming; inclusion of human emissions is required to match observed temperatures [7] [2]. This multi-line evidence—temperature profiles, radiative measurements, and model attribution—forms the core of the scientific consensus attributing recent warming primarily to human activity.
4. How much role could the Sun plausibly play now?
Long-term reconstructions and measurements indicate the Sun’s cyclical variability is small—about a tenth of a percent over the 11-year cycle—and even multi-decadal solar changes contributed at most a few hundredths to a few tenths of a degree Celsius of warming in the early 20th century, not the bulk of modern warming [4] [5]. NASA and other agencies estimate that recent solar changes are many times too small to explain observed warming, and spacecraft-era trends show declining solar influence while surface temperatures rose, creating an empirical divergence between solar forcing and global temperature [3] [5]. That quantitative mismatch is central: small solar variability cannot account for the magnitude and spatial pattern of recent warming.
5. Multiple institutions converge, but watch for different emphases and agendas
NASA, NOAA, academic reconstructions, and synthesis reports all converge on the conclusion that natural solar variability cannot explain the recent rapid warming and that greenhouse gases are the dominant cause [3] [8] [2]. Different sources emphasize different contexts: some focus on paleoclimate natural variability [1], others on satellite-era irradiance measurements [4], and some on model-attribution experiments [7]. Political or interest-group messaging can overstate natural drivers or solar influence; by contrast, the scientific assessments combine observations, theory, and models to quantify contributions. The comprehensive picture shows natural variability exists but is insufficient to explain the speed and pattern of the warming observed since the mid-20th century [2] [6].