Significant anthropogenic-induced changes of climate classes since 1950

Area of Science:

• Climate Science
• Environmental Science
• Earth System Science

Background:

• Global and regional warming trends observed in recent decades are linked to anthropogenic forcings.
• Terrestrial precipitation patterns are also likely influenced by these human-induced changes.

Purpose of the Study:

• To examine shifts in major Köppen climate classes using gridded observational data.
• To differentiate between natural climate variability and anthropogenic influences on observed climate changes.

Main Methods:

• Analysis of gridded observational data from 1950-2010.
• Utilizing control simulations from Coupled Model Intercomparison Project 5 (CMIP5) to assess internal climate variability.
• Comparison of CMIP5 multi-model averaged historical simulations with observed data, using both natural and anthropogenic forcing components.

Main Results:

• Approximately 5.7% of the global land area has transitioned to warmer and drier climate types.
• Observed changes include the expansion of arid and high-latitude continental climates and shrinkage of polar and midlatitude continental climates.
• Poleward shifts in temperate, continental, and polar climates, along with increasing average elevations for tropical and polar climates, were identified.

Conclusions:

• Observed shifts in climate types since 1950 cannot be attributed to natural climate variations alone.
• Anthropogenic factors are the primary drivers of the documented changes in global climate classes.