Earth's energy imbalance (EEI):

current knowledge and future

challenges

Dr. Matt Palmer

EEI must be central to our thinking around

climate change:

EEI must be central to our thinking around

climate change:

• Most fundamental and robust measure of the rate

of global change

EEI must be central to our thinking around

climate change:

• Most fundamental and robust measure of the rate

of global change

• Key to projections of future sea level rise

(the time history of forcing matters)

EEI must be central to our thinking around

climate change:

• Most fundamental and robust measure of the rate

of global change

• Key to projections of future sea level rise

(the time history of forcing matters)

• Observations of EEI must be sustained and

extended to the deep ocean

For a stable climate:

incoming energy = reflected energy + emitted energy

Greenhouse gases reduce emitted energy

Global warming is the result of excess solar

energy accumulating in the Earth System

Global warming is the result of excess solar

energy accumulating in the Earth System

The RATE of global warming is defined by EEI

von Schuckmann et al [submitted]

von Schuckmann et al [submitted]

Ocean heat content (OHC) accounts for > 90% of EEI

von Schuckmann et al [submitted]

von Schuckmann et al [submitted]

The symptoms of Earth’s energy imbalance

Credit: John Kennedy

Credit: John Kennedy

Credit: John Kennedy

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Credit: John Kennedy

Palmer and McNeall [2014]

Palmer and McNeall [2014]

Temperature is a poor indicator of EEI over a decade

Palmer and McNeall [2014]

OHC change is a reliable indicator of EEI over a decade

Palmer and McNeall [2014]

Credit: Simon Good

Observations of OHC: historical ocean profiles 0-700m

Observations of OHC: The Argo array of profiling floats

Observations of OHC: The Argo array of profiling floats

Roemmich et al [2015]

von Schuckmann et al [submitted]

Observations of OHC: The Argo array of profiling floats

Loeb et al [2012]

Observations of EEI: Clouds and Earth’s Radiant Energy

System (CERES, NASA)

Net Energy

Outgoing long-wave energy Reflected short-wave energy

Credit: NASA

Observations of EEI: Clouds and Earth’s Radiant Energy

System (CERES, NASA)

What about the

future..?

Surface temperature rise under climate change

Ocean heat content (OHC) rise under climate change

EEI and OHC must be central to our thinking

around climate change:

• Most fundamental and robust measure of the rate

of global change

• Key to projections of future sea level rise

(the time history of forcing matters)

• Observations of EEI must be sustained and

extended to the deep ocean (for OHC)

Questions..?

Thanks to:

Dan Bernie, Simon Good,

Jonathan Gregory, John Kennedy

Chris Roberts, Kevin Trenberth,

Karina von Schuckmann

Additional slides..

How do Argo

floats work?

Church et al [2011]

OHC change accounts for 30-40% global sea level rise

Church et al [2011] IPCC AR5 [Church et al, 2013]

OHC change accounts for 30-40% global sea level rise

IPCC AR5 Summary for Policy Makers

Symptoms of Earth’s energy imbalance..

IPCC AR5 Summary for Policy Makers

Symptoms of Earth’s energy imbalance..

IPCC AR5 [Myhre et al, 2013]

Radiative forcings give rise to Earth’ energy imbalance

Observations AND climate models tell us we must measure the deep ocean in

order to reliably track EEI and global sea level rise

Purkey and Johnson [2010]

Key points #1:

1. Earth’s energy imbalance (EEI) is the most fundamental aspect of

climate change science (and should be central to our thinking around

this topic)

2. The various aspects of observing climate change are *symptoms* of

the EEI

3. On multi-decadal timescales surface temperature rise (most used

metric of global change?) responds to climate (radiative) forcings

4. However, on decadal timescales there is little or no correspondence

between EEI and trends in surface temperature. Thus, much of the

discussion around the “hiatus” may be missing the point (?)

5. This is because the ocean is a dynamic fluid, and can re-arrange heat.

Total ocean heat content constitute > 90% of planetary heating

associated with EEI

Key points #2:

6. Highlight two critical (and highly complementary) advances in Earth

system observations: (i) CERES netTOA measurements; (ii) Argo

observations of OHC

7. Briefly describe the strengths and weaknesses of each: (i) excellent

coverage and information on radiative components, but unknown

absolute value; (ii) high absolute accuracy but large sampling “noise”

and under-sampled regions (ice covered, shallow seas, deep ocean)

8. EEI and OHC behave very differently to surface temperature under

future climate scenarios. Show RCP4.5 and RCP8.5. for surface

temperature and global thermal expansion (sea level).

9. MUST consider EEI and it’s evolution in our thinking

communication around climate change. Importance of maintaining

CERES, Argo and extending the Ocean Observing system.