Moderne klimaendringer

Study Notes

Modern climate change refers to the observed increase in global average temperatures since the pre-industrial era (approximately 1850-1900).
This warming trend is primarily driven by human activities, particularly the emission of greenhouse gases.
The increase in greenhouse gases traps more heat in the Earth's atmosphere, leading to a gradual warming effect.
Key greenhouse gases include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).
These gases absorb and re-emit infrared radiation, warming the planet.

Temperature anomalies are deviations from the long-term average temperature.
Recent years have seen significant positive temperature anomalies.
These anomalies indicate that the current temperatures are higher than the average temperature over a longer period.
Global average temperature records show a clear upward trend over the past century.
Regional variations also exist in temperature anomalies, with some regions experiencing more pronounced warming than others.

Recent climate change encompasses the warming trend observed in the last century and specifically in the past few decades.
This period of accelerated warming has led to noticeable changes across the globe.
Changes include: rising sea levels, more frequent and intense heatwaves, changes in precipitation patterns, and more extreme weather events.
The speed and magnitude of recent climate change are unprecedented in the context of the past thousands of years.

Blackbody radiation is the thermal electromagnetic radiation emitted by a black body in thermal equilibrium with its surroundings.
A black body absorbs all incident electromagnetic radiation and emits radiation based on its temperature.
The intensity and spectrum of the emitted radiation are determined by the temperature.
The hotter the black body, the more intense and shorter the wavelength of radiation it emits.

Electromagnetic radiation encompasses a wide range of energy forms, including radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.
These forms differ in wavelength and frequency.
The sun emits a broad spectrum of electromagnetic radiation, which plays a crucial role in Earth's climate system.
Some types of radiation, like infrared, are absorbed and re-emitted by greenhouse gases.

The primary source of energy driving Earth's climate system is solar radiation.
Solar radiation, primarily in the form of visible light, is absorbed by the Earth's surface and atmosphere.
This absorbed energy is then re-radiated back into space as heat (infrared radiation).
Greenhouse gases in the atmosphere trap some of this outgoing infrared radiation, leading to a warming effect.
The increase in greenhouse gas concentrations due to human activities enhances this natural warming process, resulting in the observed global warming.
Without this natural phenomenon of the greenhouse effect, Earth's average temperature would be significantly lower and life as we know it might not exist.