Evidence of Climate Change: Scientific Proof and Real-World Impacts
Climate changes have occurred on Earth in different geological periods from the past to the present. Evidence of climate change is found in other parts of land and watersheds. This is discussed below—
- Ice layer analysis: Drilling into the ice in Greenland and Antarctica collects deep layers of ice. It tests the ratio of light to heavy oxygen in the ice and the air bubbles trapped in it. By getting an idea of the amount of CO₂ in the air, it is possible to identify the nature of the past climate. Radioisotope tests of continental ice sheets show that Antarctica was 5°C cooler than today 60,000 years ago. Temperatures fell again 30,000 years ago.
- Glacial advance and retreat in the past: Evidence of glacial advance and retreat during different ice ages and interglacials shows climate change. 100,000-year-old fossils in Antarctica and Greenland have been dated using radioisotopes. From the available data, the ice line receded between the seventeenth and nineteenth centuries. Again, in this context, the climate of the Sumeru region was relatively warm in the first half of the twentieth century. Many pieces of evidence of glacier advance and retreat can be seen in regions like Canada, Siberia, etc.
- Sediment studies: Deep ocean floor sediment samples can prove past climates were different from the present. Sandstones indicate dry climates, and mudstones and silts indicate humid climates.
- Accumulation of silt, salt, and soil: Elevated around the present lake, sandstone deposits refer to glacial kettle lakes and gravel line deposits from the Ice Age. Again, the accumulation of salinity is seen in the present-day high deserts of Africa, Asia, Australia, and North and South America. Lakes formed in past humid climates. As temperatures rose, evaporation increased. It dried up the lakes, creating salinity. Ancient climates can be analyzed by analyzing ancient soils on river floodplains, altered soils deposited on lake shores, and peat soils.
- Sea-level change: continental glaciation and climate melting increase the sea’s water and water level. Again, water turns into ice in colder climates. As a result, the area of the continental glaciers increased and the sea level decreased as the sea level decreased. Therefore, if the sea level is high, it indicates a warm climate; if it is low, it indicates a cool climate. The Pleistocene saw sea levels rise and fall. This marked the arrival and return of glaciations and interglacials.
- Existence of salt mines: The location of salt mines in arid desert regions indicates the existence of a humid climate in the past. Formerly, there was a lake in the area, and later, due to climate change, the water evaporated and formed the salt mine.
- Archaeological soil surveys: We can find evidence of climate change by studying ancient soils in lake regions, plateaus, wetlands, or deserts.
- Fossils:
Animal Fossils: The remains of plankton in marine sediments can inform us about seawater and surface air pressures. Hippopotamus fossils found in the Netherlands indicate the climate of tropical East Africa 10 million years ago. Again, dinosaur fossils prove that they thrived in wet and dry climates and perished in colder climates.
Plant Fossils: Coal deposits in the mid-latitudes of the Northern Hemisphere bear evidence of a humid climate in the past. Fossils of the ferns Glossopteris and Gangamasteris in India, Australia, Africa, South America, and Antarctica show evidence of ancient cool, wet climates.
- Study of ancient soils: We can find evidence of climate change by studying ancient soils in plateaus, lake regions, wetlands, or deserts.
