A report from the European Meteorological Society’s annual meeting 2018

If you want to make a difference as a scientist, you need to make sure that people understand the importance of your work. Conferences give you one opportunity to explain what you’ve found out. I sometimes wonder if the value of attending conferences is sufficiently appreciated. You can save time getting an overview over your field of research and catch up on the latest developments, which would take many weeks just from

Are the heatwaves caused by climate change? 

I get a lot of questions about the connection between heatwaves and climate change these days. Particularly about the heatwave that has affected northern Europe this summer. If you live in Japan, South Korea, California, Spain, or Canada, you may have asked the same question. The raindrop analogy However, the question is inaccurate and I will try to explain this through an analogy. Let’s say I go for a walk with a friend and my friend feels a few drops of water that fall on her. She asks me if it’s raining. But as long as there was only few drops of water, it could also be something else. I tell her that we can get

Climate indicators

The climate system is complex, and a complete description of its state would require huge amounts of data. However, it is possible to keep track of its conditions through summary statistics. There are some nice resources which give an overview of a number for climate indicators. Some examples include NASA and The Climate Reality Project. The most common indicator is the atmospheric background CO2 concentration, the global mean temperature, the global mean sea level, and the area with snow or Arctic sea ice. Other indicators include rainfall statistics, drought indices, or other hydrological aspects. The EPA provides some examples. One challenge has been that the state of the hydrological cycle is not as easily summarised

A brief review of rainfall statistics

There have been a number of studies which show that we can expect more extreme rainfall with a global warming (e.g. Donat et al., 2016). Hence, there is a need to increase our resilience to more rainfall in the future. We can say something about how the rainfall statistics will be affected by a global warming, even when the weather itself is unpredictable beyond a few days. Statistics is remarkably predictable for a large number of events where each of them is completely random (welcome to thermodynamics and quantum physics). The normal distribution has often been used to describe the statistical character of daily temperature, but it is completely unsuitable for 24-hr precipitation. Instead, the gamma distribution has

Impressions from the European Meteorological Society’s annual meeting in Dublin 

The 2017 annual assembly of the European Meteorological Society (EMS) had a new set-up with a plenary keynote each morning. I though some of these keynotes were very interesting. There was a talk by Florence Rabier from the European Centre for Medium-range Weather Forecasts (ECMWF), who presented the story of ensemble forecasting. Keith Seitter, the executive director of the American Meteorological Society (AMS), talked about the engagement with the

Why extremes are expected to change with a global warming

Joanna Walters links extreme weather events with climate change in a recent article in the Guardian, however, some reservations have been expressed about such links in past discussions. For example, we discussed the connection between single storms and global warming in the post Hurricanes and Global Warming – Is there a connection?,

What do you need to know about climate?

What do you need to know about climate in order to be in the best position do adapt to future change? This question was discussed in a European workshop on Copernicus climate services during a heatwave in Barcelona, Spain (June 12-14). The answer is not clear-cut, even after having some information about user requirements from a survey to identify a direction for data evaluation for climate models (DECM). The survey is still carried out. Some of the key issues

Snow Water Ice and Water and Adaptive Actions for a Changing Arctic

The Arctic is changing fast, and the Arctic Council recently commissioned the Arctic Monitoring and Assessment Programme (AMAP) to write two new reports on the state of the Arctic cryosphere (snow, water, and ice) and how the people and the ecosystems in the Arctic can live with these changes. The two reports have now just

The true meaning of numbers

Gavin has already discussed John Christy’s misleading graph earlier in 2016, however, since the end of 2016, there has been a surge in interest in this graph in Norway amongst people who try to diminish the role of anthropogenic global warming. I think this graph is warranted some extra comments in addition to Gavin’s points because it is flawed on more counts beyond those that he has already discussed. In fact, those using this graph to judge climate models reveal an elementary lack of understanding of climate data. Fig. 1. Example of Christy’s flawed evaluation taken from Comparing models to the satellite datasets. Different

New report: Climate change, impacts and vulnerability in Europe 2016

Another climate report is out – what’s new? Many of the previous reports have presented updated status on the climate and familiar topics such as temperature, precipitation, ice, snow, wind, and storm activities. The latest report Climate change, impacts and vulnerability in Europe 2016 from the European Environment Agency (EEA) also includes an assessment of hail, a weather phenomenon that is often associated with lightening (a previous report from EASAC from 2013 also covers hail). Usually, there has not been a lot of information about hail, but that is improving. Still, the jury is still out when it comes to hail and climate change: Despite improvements in data availability, trends and projections of hail events are still uncertain. EEA 2016 report

A trigger action from sea-level rise?

Can a rising sea level can act as a boost for glaciers calving into the sea and trigger a surge of ice into the oceans? I finally got round to watch the documentary Chasing Ice over the Christmas and New Year’s break, and it made a big impression. I also was left with this question after watching it. There is a connection between the unfolding events in the polar regions and our lives. The

What is new in European climate research?

The EMS 2016 Venue What did I learn from the 2016 annual European Meteorological Society (EMS) conference that last week was hosted in Trieste (Italy)? I think the biggest news from the conference was that new reanalyses are soon to be released by the European Centre for Medium-ranged Weather Forecasts (ECMWF). One new product known as ERA-5 will replace the older called ERAINT, and preliminary results suggest a significant improvement in addition to higher

Do regional climate models add value compared to global models?

Global climate models (GCM) are designed to simulate earth’s climate over the entire planet, but they have a limitation when it comes to describing local details due to heavy computational demands. There is a nice TED talk by Gavin that explains how climate models work. We need to apply downscaling to compute the local details

Scientists getting organized to help readers sort fact from fiction in climate change media coverage

Guest post by Emmanuel Vincent While 2016 is on track to easily surpass 2015 as the warmest year on record, some headlines, in otherwise prestigious news outlets, are still claiming that “2015 Was Not Even Close To Hottest Year On Record” (Forbes, Jan 2016) or that the “Planet is not overheating…” (The Times of London, Feb 2016). Media misrepresentation confuses the public and prevents our policy makers from developing a well-informed perspective, and making evidence-based decisions. Professor Lord Krebs recently argued in an opinion piece in The Conversation that “accurate reporting of science

What is the best description of the greenhouse effect?

What exactly is the greenhouse effect? And what does it look like if we view it from a new angle? Of course, we know the answer, and Raymond Pierrehumbert has written an excellent paper about it (Infrared radiation and planetary temperature). Computer code used in climate models contain all the details. But is it possible to provide a simple description that is physically meaningful and more sophisticated than the ‘blanket around earth’ concept? I wanted a description that could be grasped by physicists. Without

Anti-scientists

Ross McKitrick was so upset about a paper ‘Learning from mistakes in climate research’(Benestad et al., 2015) that he has written a letter of complaint and asked for immediate retraction of the pages discussing his work. This is an unusual step in science, as most disagreements and debate involve a comment or a response to the original article. The exchange of views, then, provides perspectives from different angles and may enhance the understanding of the problem. This is part of a learning process. Responding to McKitrick’s letter, however, is a new opportunity to explain some basic statistics, and it’s excellent to have some real and clear-cut examples

Noise on the Telegraph

I was surprised by the shrill headlines from a British newspaper with the old fashioned name the Telegraph: “The fiddling with temperature data is the biggest science scandal ever”. So what is this all about? The story makes serious allegations, however Victor Venema explains why the Telegraph got it wrong in Variable Variability, and makes the point that three hand-picked stations from Paraguay – out of thousands – hardly matters. He also shows the effect of post-processing on the global mean temperature: it reduces the global trend compared to raw data. The story also sparked some discussion