Climate Variability and Change: Introduction to Course

 

Climate Variability and Change: Introduction to Course

 

Observed long-term trends: manmade or natural?

Climate Variability and Change: Introduction to Course

 

The coupled climate system has important natural variability

Climate Variability and Change: Introduction

 

Temperature anomalies for July 2010

Climate Variability and Change: Introduction

 

Climate Variability and Change: Introduction

 

Climate Variability and Change: Introduction

 

Climate Variability and Change: Introduction

 

What are the causes of the observed anomalies?

Climate Variability and Change: Introduction

 

Can we predict these anomalies a season ahead?

Climate Variability and Change: Introduction

 Was the hot July in Western Europe part of a global warming signal?

Climate Variability and Change: Introduction

 Was the hot July in Western Europe part of a global warming signal caused by us?

Climate Variability and Change: Introduction

 The global average temperature for July 2013 was 0.61oC above the 20th Century average. Is this a global warming signal?

Global Highlights

The combined average temperature over global land and ocean surfaces for July 2013 was the sixth highest on record, at 0.61°C (1.10°F) above the 20th century average of 15.8°C (60.4°F).

The global land surface temperature was 0.78°C (1.40°F) above the 20th century average of 14.3°C (57.8°F), marking the eighth warmest July on record. For the ocean, the July global sea surface temperature was 0.54°C (0.97°F) above the 20th century average of 16.4°C (61.5°F), the fifth warmest July on record.

The combined global land and ocean average surface temperature for the January–July period (year-to-date) was 0.59°C (1.06°F) above the 20th century average of 13.8°C (56.9°F), tying with 2003 as the sixth warmest such period on record.

Climate Variability and Change: Introduction

 

Climate Variability and Change: Introduction

 

July 2013 was a warm one in the Northeast. Eleven of the twelve Northeast states ranked this July among their top 20 warmest with Rhode Island and Massachusetts having their warmest July on record. Twenty-six of the thirty-five first order sites ranked this July among their top 20 warmest, with three sites setting monthly temperature records.

Climate Variability and Change: Introduction

 

Climate Variability and Change Affects Society

Climate impacts:food and waterhealthinfrastructure and

transportdemographyenergy

The Sahel (15-20N)

The Sahel experienced one of the most dramatic decadal signals last century

Climate Variability and Change Affects Society in the US

Climate impacts:food and waterhealthinfrastructure and

transportdemographyenergy

Flooding in New Orleans due to Katrina (courtesy NOAA)

Bonnie (05)

Charlie (05)

Frances (05)

Ivan (05)

courtesy A. Aiyyer

Climate Variability and Change Affects Society in the US

Climate Variability and Change Affects Society in the US

 

Society demands useful predictions of climate so that it can respond to climate variability.

One key question to ask is: What do the users of these forecasts need?

 

In recent years most seasonal predictions have been concerned with providing the mean seasonal rainfall anomaly – not always useful. Users tend to want more than this – when will the rainy season start? How will the rainfall be distributed within the season (weather?)? These are much harder to predict.

 

Science and Society Interact

 

 

Limits of predictability

weather – theoretically 1-2 weeks – TOPS!; currently much less than this, probably around 5 days or so – limitations include poor models and poor observations of the atmosphere especially.

 

climate – forecasts are made at seasonal-to-interannual and multi-decadal timescales (including climate change) – limitations include poor models, poor observations of “climate system” – includes land and ocean , less important for weather.

 

 

 

 

 

•Seasonal-to-Interannual variability

We will discuss the basis for these forecasts in this course.

Need to understand causes of seaonal-to-interannual variability.

 

 

 

 

 

At these timescales it is crucial to provide information on the status of ENSO and to be able to predict the impacts of ENSO locally and around the globe (teleconnections).

  

 

 

•Multidecadal Fluctuations and Trends

Efforts are also made to make predictions on longer timescales

  

 

Introduction to the course

  

 

 Section 1: Introduction to the Climate System

Provides background to the mean climate system, combines observations of key variables of the climate system and a physical understanding of key processes. These sections are required for a basic understanding of the climate system and processes before we can attempt to consider its variability. Many textbooks exist that cover these areas.

  

 

 Section 2 Natural Climate Variability

We will consider the nature of observed seasonal-to-interannual variability – (things we wish to predict) - Most importantly in this section is ENSO (observations, mechanisms and impacts (teleconnections).

In addition we will discuss decadal variability – important to be aware of this when attempting to attribute anomalies to a “global warming” trend.

We will discuss how climate predictions are made

Finally we will consider how climate variability is manifested in changes in high impact weather.

  

 

 Section 3 Climate Change

We will consider the theory of climate change

We will look at the observational evidence as well as how climate predictions are consistent (or not) with this.

The IPCC process will be discussed

  

 

 Section 4 Future Perspectives

We will finish with some discussion on how science and society are interacting with regards to climate variability and change.

  

 

 Section 4 Future Perspectives

  

 

 Section 4 Future Perspectives

  

 

 Section 4 Future Perspectives

What can we do?

‘We basically have three choices: mitigation,adaptation and suffering.

We’re going to do some of each.

The question is what the mix is going to be.

The more mitigation we do, the less adaptation will be required and the less suffering there will be.’

John Holdren,Former President, American Association for the Advancement of Sciencenow Director of the White House Office of Science and Technology Policy(OSTP)

We need a new generation of young scientists to solveour future energy problems – education is key!

Final

5 questions equally approximately equally weighted:

3 questions on Natural Variability

AMO

ENSO

Prediction

Weather versus Climate

2 questions on Climate Change

Theory of climate change

Modeling – past and future

Other Climate-Related Courses

Spring 2014

ATM405 Water and Climate Change

ATM413 Weather, Climate Change and Societal Impacts

ENV480 Climate Modeling

Fall 2014

ATM404 Oceans and Climate

SIRFs

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•In comments please can you address waiting of Natural versus Climate Change content.

•Also – anything you would have liked to have seen?

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