The Earth System in The
Anthropocene
Jón Egill Kristjánsson
Overview
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What is the Earth System?
What is the Anthropocene?
What is Radiative Forcing?
What do we mean by Climate Feedbacks?
What are the main causes of Uncertainty?
Earth System Models
Future Projections
What is ‘the Earth System’?
• Earth system science seeks to integrate various fields
of academic study to understand the Earth as a system.
It considers interactions between the atmosphere,
hydrosphere, solid Earth (lithosphere and deeper),
biosphere, and heliosphere, as well as the impact of
human societies on these components.
• At its broadest scale, Earth system science brings
together researchers across both the natural and social
sciences, from fields including ecology, economics,
geology, glaciology, meteorology, oceanography,
paleontology, sociology and space science.
(source: Wikipedia)
What is ‘the Anthropocene’?
• The Anthropocene is a proposed epoch that begins
when human activities started to have a significant
global impact on Earth's ecosystems.
• The term has been widely popularized by atmospheric
chemist, Paul Crutzen, who regards the influence of
human behavior on the Earth's atmosphere in recent
centuries as so significant as to constitute a new
geological epoch.
• As of April 2015, the term has not been adopted
formally as part of the official nomenclature of the
geological field of study.
(source: Wikipedia)
Drivers of Climate Change
What is ‘Radiative Forcing’?
Radiative Forcing 1750 - 2011
Greenhouse Gases 1950 - 2030
CO2
CH4
N2O
Climate Feedbacks
Climate Feedbacks: Changes in the System
that Enhance (+) or Dampen (-) the Signal
Surface Temperature 1950 - 2030
Sea Level 1950 - 2030
Changes in Extreme Events
Changes in Extreme Events
Extreme Heat Wave – Europe 2003
Swiss Temperature Data 1864-2003
June/July/August Temperature Anomaly
Schär et al. (2004: Nature)
Changing Statistical Behavior in a
Changing Climate
Regional Climate Model Simulations
Schär et al. (2004: Nature)
Sources of Uncertainty
IPCC Terminology concerning
Uncertainty
Climate Model Evolution
1970s – 2010s
Model Resolution
Near-future Global Climate
Models
Regional Climate Models
Future Scenarios
Future Scenarios
The figure shows radiative forcings. How do we relate it to the ‘2-degree
target’ (temperature change)?
Scenarios  CO2 and CFC
concentrations