Category Archives: uncertainty

Reliability of regional climate trends

Posted on April 15, 2013 by Ed Hawkins

Climate information for the future is usually presented in the form of scenarios: plausible and consistent descriptions of future climate without probability information. This suffices for many purposes, but for the near term, say up to 2050, scenarios of emissions … Continue reading →

Posted in GCMs, observations, projections, temperature, uncertainty, variability | 3 Comments

Constraining projections with observations

Posted on February 20, 2013 by Ed Hawkins

Can past observations be used to help constrain future temperature projections? This question is particularly relevant given the last decade which has shown relatively less warming than expected.

Posted in GCMs, observations, projections, temperature, uncertainty | 15 Comments

Updated comparison of simulations and observations

Posted on February 8, 2013 by Ed Hawkins

Now that 2012 is over, it is time to update a comparison of simulations and observations of global mean temperatures.

Posted in GCMs, observations, projections, temperature, uncertainty | 48 Comments

Visualising the role of natural variability

Posted on August 22, 2012 by Ed Hawkins

A new analysis by Clara Deser and colleagues (accepted for Nature Climate Change), provides some fantastic visualisations of the crucial role of natural variability in how we will experience climate.

Posted in GCMs, projections, temperature, uncertainty, variability, visualisation | 14 Comments

Projections of maize yields in France

Posted on June 14, 2012 by Ed Hawkins

A rather specific question today – what will happen to maize yields in France in 2016-2035?

Posted in crops, precipitation, projections, temperature, uncertainty, variability | 3 Comments

On comparing models and observations

Posted on March 14, 2012 by Ed Hawkins

There has been some recent blog discussion on comparing observations and climate models consistently. Here is my effort at such a comparison using the CMIP5 models which are already available.

Posted in GCMs, projections, uncertainty, variability | 97 Comments

The importance of reliable uncertainty estimates

Posted on January 3, 2012 by Ed Hawkins

Reliable estimates of uncertainty are arguably more important than the actual value being quoted. I recently came across a classic example in astronomy.

Posted in uncertainty | 14 Comments

Time of emergence of climate signals

Posted on December 5, 2011 by Ed Hawkins

The time at which the signal of climate change emerges from the ‘noise’ of natural climate variability (Time of Emergence, ToE) is a key variable for climate predictions and risk assessments.

Posted in GCMs, temperature, uncertainty, variability | 3 Comments

Uncertainty in temperature variability

Posted on November 13, 2011 by Ed Hawkins

It is well known that there is considerable uncertainty in the projected response of climate models to increases in radiative forcing. However, there is also considerable uncertainty in the model simulated internal variability.

Posted in GCMs, temperature, uncertainty, variability | 1 Comment

Climate uncertainty: moving from ‘what’ to ‘when’

Posted on September 27, 2011 by Ed Hawkins

Update (23/10/11): The full article has now been published in Nature Climate Change Climate projections (such as from the IPCC) usually consider the question of “what will happen to our future climate”. But, this question may be more informative if … Continue reading →

Posted in GCMs, projections, temperature, uncertainty | 7 Comments

Uncertainty in uncertainty

Posted on August 24, 2011 by Ed Hawkins

There has been much discussion recently on whether GCMs participating in intercomparisons, such as CMIP3 and CMIP5, are ‘independent’. But if they are not, how does this make a difference to the uncertainty in our projections for future climate?

Posted in GCMs, projections, temperature, uncertainty | 3 Comments

Visualising climate with 2d colour bars

Posted on July 10, 2011 by Ed Hawkins

A recent paper by Teuling et al. suggested the use of 2d colour bars for visualising climate fields. I thought I would give this a try – and Ryan Teuling was kind enough to provide the code to construct the … Continue reading →

Posted in precipitation, projections, uncertainty, visualisation | 1 Comment

When to use uncertain climate forecasts

Posted on May 12, 2011 by Ed Hawkins

Climate models produce projections of changes in climate from the present day, but these projections have a range, or spread. A simple measure of the confidence in a forecast would be the signal-to-noise ratio, r, of the size of the … Continue reading →

Posted in GCMs, precipitation, projections, uncertainty | Leave a comment

Communicating climate variability

Posted on August 11, 2010 by Ed Hawkins

Update 10/03/11 – Accepted article also online. Comments very welcome. Communicating the differences and links between climate variability and climate change is of growing importance, and I am currently writing an article for “Weather” on this.

Posted in GCMs, projections, temperature, uncertainty, variability | Leave a comment