The temperature curve on a geologic time scale and the current global temperature curve represent different aspects of Earth's temperature history.
Geologic Time Scale Temperature Curve: The temperature curve on a geologic time scale represents long-term changes in Earth's climate over millions of years. It provides an overview of how global temperatures have varied over geological epochs and eras. This curve is constructed using various proxies and indicators, such as isotopic analysis of ice cores, sedimentary records, and fossilized remains. It helps scientists understand past climate dynamics, including periods of cooling (ice ages) and warming (interglacial periods).
Current Global Temperature Curve: The current global temperature curve, often referred to as the global temperature record, tracks the changes in average global surface temperature over recent decades or centuries. It is based on direct measurements from weather stations, satellites, and other sources. This curve provides a more detailed and precise depiction of temperature fluctuations during the modern era. It reflects the impact of human activities, particularly greenhouse gas emissions, on Earth's climate system. The current global temperature curve shows a pronounced and accelerated warming trend since the mid-20th century.
In summary, the temperature curve on a geologic time scale encompasses long-term climatic changes over geological epochs, while the current global temperature curve focuses on recent and ongoing changes in Earth's temperature, especially in relation to human-induced climate change.