Reporting the weather across the UK

8 01 2016

December 2015 was the wettest calendar month for the UK in a series of monthly weather records stretching back to 1910. But why does the Met Office state 1910 when listing records, especially when some records existed well before that time?

Part of the answer is that the Met Office has a responsibility to collate weather records for the entire UK, the UK countries and historic counties.  The digital archive used to generate our UK analyses includes station observations back to 1853, but only since 1910 has there been a sufficiently dense network of stations to allow an analysis of the whole UK.

One station, the Oxford Radcliffe Observatory, which is managed by Oxford University School of Geography and the Environment – holds rainfall records back to 1767. This allows a greater understanding of the rainfall in Oxfordshire, but doesn’t allow greater comparison with England or the UK: vital when you are trying to provide a complete picture.

The England and Wales Precipitation (EWP) series stretches back to 1766. In recent times the EWP – a highly significant climate series – is based on records from around 100 stations, but the further you go back the fewer recording stations there were. This provides a good analysis of records for England and Wales, but doesn’t capture the remainder of the UK: Scotland and Northern Ireland. Additionally, it doesn’t take account of the thousands of recording stations which provide more detailed picture for the UK in more modern times.

Dr Mark McCarthy is the head of the Met Office’s National Climate Information Centre. Commenting on the results he said: “Although our UK dataset currently only stretches back to 1910 we are adding to it by digitising more of our extensive paper archives in order to extend these records further back in time. When we have done that it is possible that months like October 1903 may rival or even surpass some of the UK records set in December 2015.

“However for December 2015 we have a good picture  of the rainfall patterns across the UK such as the record breaking rainfall in: Cumbria, North Wales; eastern Dumfries and Galloway; and parts of the Cairngorms.”

December 2015 rainfall anomaly map

December 2015 rainfall anomaly map

“In fact, as our very high-resolution rainfall map in December 2015 shows, parts of England were close to average and some places actually recorded lower than average precipitation. Just like a digital photograph, greater resolution allows you to observe finer detail.  Therefore picking any one place or region may not be representative of the UK as a whole.”

Met Office national records are created using a method to interpolate observations from our network of stations onto a 5km by 5km grid covering the UK. The gridding method is a more sophisticated approach for analysing rainfall than simply taking an average of station data. However, because it also requires a denser network of stations it is not as long running a series as the EWP and some long running observing sites. The different datasets are therefore complementary and we use both to monitor our changing climate.

So, the UK’s national climate series – the records you will see quoted when the Met Office routinely releases statistics – is a comprehensive rainfall analysis covering the whole of the UK back to 1910 using all available observations. Other series including the EWP are also a vital part of our national climate monitoring and provide us with an even longer historical context for some parts of the UK.

Professor Adam Scaife is a climate scientist with the Met Office’s Hadley Centre. He said: “It’s clear that December 2015 was a very significant month for rainfall and was the highest since our records began in 1910.  We have been asked about the link between climate change and the rainfall in December 2015.

“With or without climate change there have always been exceptional spells of weather and there always will be. But climate change can add to the natural variations in our climate and it is this that increases the chance of record breaking weather and unprecedented extremes.  It is therefore vital that we monitor our weather and climate in as much detail as possible to assess and predict future weather extremes.”





The science questions following a global deal on climate

15 12 2015

There has been a huge amount of worldwide media coverage following the weekend’s announcement of a globally agreed deal to try to limit global warming to 2 °C or less. Here Professor Stephen Belcher, the Director of the Met Office’s Hadley Centre for Climate Science and Services, discusses some of the scientific questions raised by the agreement.

At the heart of the Paris agreement is the aim to hold “the increase in the global average temperature to well below 2 °C above pre-industrial levels”*. Why 2 °C? Because global governments have previously agreed this is an achievable target which could reduce some of the most dangerous impacts of climate change – such as melting of ice in places like the Greenland which would cause large scale sea level rise.

The agreement went even further, however, by saying efforts should be pursued to “limit the temperature increase to 1.5 °C”. This is a more ambitious target, especially given news from the Met Office in November that the world has reached the 1 °C above pre-industrial marker for the first time this year.

It raises some interesting questions for scientists as to how we can achieve this: how much do we need to cut global greenhouse gas emissions? How quickly do we need to make those cuts? What else might we need to do to be able to keep warming to 1.5 °C – for example, would we need to develop technologies that actually remove CO2 from the atmosphere? If temperatures overshot 1.5 °C and then reduced to 1.5 °C, would sea level also overshoot and then reduce?

To answer these questions more precisely will require scientists to get an even more detailed understanding of how sensitive our climate is to CO2 and other greenhouse gases.

Key to this will be improving understanding of what we call ‘Earth system feedbacks’. These are natural feedback processes which could either increase or decrease the amount of warming we might expect in response to a given amount of greenhouse gases. For example, we know that there are stores of greenhouse gases ‘locked away’ under frozen ground (permafrost) in some parts of the world, such as northern  Russia. If that permafrost melts due to climate change, the gases would be released – which could further increase warming.

Scientists around the world are already working on providing answers to these questions by developing a new breed of ‘Earth System Models’ (essentially complex simulations of our planet run on powerful supercomputers), which take more of these feedback processes into account, and so will help inform planning of emissions to achieve the warming targets agreed in Paris.

Whether we limit warming to 2 °C or 1.5 °C, it’s clear we can expect some further change to our global climate over the coming decades. Research shows us that this will lead to some impacts and it’s vital that we understand in more detail what this means at a regional and local level.

For example, research tells us that some parts of the world can expect more extreme weather – including heat waves and increases in extreme rainfall. For those planning everything from future homes, to flood defences, to vital infrastructure, the detail on what to expect is essential.

Again, these are questions which science is already working to answer by harnessing new research and ever more powerful supercomputing technology. At the Met Office, we’ve published papers showing that we can expect more intense summer downpours for the UK in future – which raises the risk of flash flooding. We’ve also shown how the chances of summer heatwaves in Europe have dramatically increased.

There’s still much more work to do in this area and it will be vital that the information generated by this research is presented in a way that allows everyone to make informed decisions about how we can become more resilient to our climate – whatever changes we can expect.

*There’s a lot of scientific debate about exactly what ‘pre-industrial levels’ means and how you would measure that, but here we use the average of temperatures during the period 1850-1899 as our representation.





Did climate change have an impact on Storm Desmond?

7 12 2015

The exceptional rainfall in Cumbria over the past few days saw the fall of numerous records and has led many to ask whether it is linked to climate change. The records are based on digitised data going back to the 19th Century.

A gauge at Honister Pass recorded 341.4mm of rainfall in the 24-hours up to 1800 GMT on 5 December 2015, making for a new UK record for any 24-hour period. This beat the previous record of 316.4mm set in November 2009 at Seathwaite, also in Cumbria. A new 48-hour record (from 0900 to 0900 hrs) was also set, when 405mm was recorded at Thirlmere in Cumbria in just 38 hrs.

The weekend’s record rainfall was associated with a persistent, south-westerly flow bringing a ‘river of moisture’ from as far away as the Caribbean and the Gulf of Mexico. Ocean temperatures in the West Atlantic are currently well above normal and may well have contributed to the very high levels of moisture in the air masses which unleashed rainfall on the Cumbrian fells.

Professor Dame Julia Slingo, Met Office Chief Scientist, says “It’s too early to say definitively whether climate change has made a contribution to the exceptional rainfall. We anticipated a wet, stormy start to winter in our three-month outlooks, associated with the strong El Niño and other factors.

“However, just as with the stormy winter of two years ago, all the evidence from fundamental physics, and our understanding of our weather systems, suggests there may be a link between climate change and record-breaking winter rainfall. Last month, we published a paper showing that for the same weather pattern, an extended period of extreme UK winter rainfall is now seven times more likely than in a world without human emissions of greenhouse gases.”





2015 likely to be the warmest on record

25 11 2015

This year’s global average surface temperature is likely to be the warmest on record according to data from the Met Office, and is expected to continue the trend showing 15 of the top 16 warmest years have happened since 2001.

These findings concur with the World Meteorological Organisation (WMO) findings also announced today.

2015 a more ‘clear-cut’ record

Provisional figures up to the end of October show this year’s near-surface global temperature as estimated from the HadCRUT dataset has been around 0.71 ±0.1 °C above the 1961-1990 average of 14.0 °C.

This is in-line with the Met Office’s forecast, issued in December 2014, which predicted 2015 global temperatures would be between 0.52 °C and 0.76 °C* above the 1961-1990 average, with a central estimate of 0.64 °C.

In HadCRUT, this year is clearly warmer than 2014, the previous nominal warmest year in the record, which was 0.57 ±0.1 °C above the 1961-1990 average.

Global Temperature graph

Colin Morice, a climate monitoring scientist at the Met Office, said: “Last year was nominally the warmest year in our records but wasn’t much higher than the other top warmest years. This year the temperature is markedly warmer than anything we’ve previously seen in the 166-year record, meaning its position at the top of the rankings looks set to be much more clear cut.”

 

The HadCRUT dataset, jointly compiled by the Met Office and Climatic Research Unit at the University of East Anglia, uses data from more than 6, 000 observation sites around the world and observations from ships and buoys at sea. It is recognised as one of the world’s leading indices of global temperature.

Temperatures 1 °C above ‘pre-industrial’ for first time

2015 is set to mark the first time in the record that annual global temperatures reach 1 °C above ‘pre-industrial’ temperatures (taken here as an average of the 1850-1900 period*).

This is important because governments around the world have agreed the aim of trying to limit warming to 2 °C or less above pre-industrial to try to avoid the most dangerous impacts of climate change.

Leading independently-run datasets agree

Findings from HadCRUT are very similar to independently-run global temperature datasets compiled by the US National Oceanic and Atmospheric Administration and NASA Goddard Institute of Space Studies.

Information from all three datasets is included in an announcement from the World Meteorological Organization (WMO) on global temperature, which also concludes this year is likely to be the warmest on record.

Where did 2015’s warmth come from?

This year has seen a strong El Niño develop, with unusually warm sea surface temperatures across the Tropical Pacific, releasing heat into the atmosphere and pushing up global temperatures.

Global Temperature chart

Global Temperature chart

While this has contributed to 2015’s warmth, this is likely to be comparatively small compared to the long-term influence of warming caused by human greenhouse gas emissions.

This is backed up by research from the Met Office last year which showed global temperatures seen in recent years would be highly unlikely in a world without human influence on the climate.

What’s in store for the year ahead?

Last year saw record or near record warmth globally, this year is warmer still and the current expectation is that next year will also be warm.

This is due to two factors: firstly, the ongoing warming due to human influence, and secondly although the current El Niño is expected to peak around the end of this year, its main warming influence is usually felt in the months afterwards. For example, a strong El Niño peaked at the end of 1997 – but it was 1998 which went on to become a record (at the time) by some margin.

There are other natural factors – such as changes in longer term ocean cycles or volcanic eruptions – which could act to reduce global temperatures next year, so there will always be some uncertainty.

The Met Office will give more detail in the expected global temperature for 2016 when it publishes its forecast in the latter part of December.

 

* While late 19th century temperatures are commonly taken to be indicative of pre-industrial, there is no fixed period that is used as standard and a variety of other periods have been used for observational and palaeo datasets. There are limitations in available data in the early instrumental record, making the average temperature in the reference period less certain. There is not a reliable indicator of global temperatures back to 1750, which is the era widely assumed to represent pre-industrial conditions. Therefore 1850-1900 is chosen here as the most reliable reference period, which also corresponds to the period chosen by IPCC to represent a suitable earlier reference period.





So what happened to our summer?

28 08 2015

Our Chief Scientist Professor Dame Julia Slingo OBE FRS reflects on this summer’s weather and what has influenced it:

No-one can deny that we have had a pretty disappointing summer with a lot of unsettled weather and only a few warm spells, especially through July and August. Our weather has been dominated by low pressure over and to the west of the country that has brought us periods of heavy rain from the south – what we call the Spanish Plume. So what has been happening?

If we look beyond our shores there have been some big changes in the global climate this year. El Niño is in full flight, disturbing weather patterns around the world. The low pressure that has dominated our weather is part of a pattern of waves in the jet stream around the world that has brought crippling heat waves to places like Poland and Japan. And, looking back over past El Niños, you could have expected that a more unsettled summer might be on the cards for the UK. Closer to home the North Atlantic is more than 2 degrees colder than normal. It seems quite likely that the unusually cold North Atlantic has strengthened and pushed our jet stream south, also contributing to the low pressure systems that have dominated our weather.

So could all this have been anticipated? Seasonal forecasts for this summer suggested that temperatures and rainfall would be near normal. However, as the season progressed all the leading models around the world failed to capture the signal for unsettled weather over the UK. We all know that forecasting months and seasons ahead is still in its infancy and much more research needs to be done. On the other hand our day-to-day forecasts have been really successful in allowing us to warn of bad weather, highlighting yet again the benefits of our research that has delivered year-on-year and decade-by-decade improvements in forecasting skill. Our 5-day forecast is now as accurate as our 1-day forecast was when I started my career. This enables us to make so many decisions that keep us safe, protect our property, keep our infrastructure running and even when to go out and enjoy the sunshine!

All of this cannot happen without improvements to research and technology, and this week the first phase of our new supercomputer went live, five weeks ahead of schedule. This will enable us to provide even more accurate and relevant weather and climate forecasts to all of us, our government, emergency responders, and our many other customers at home and abroad.

The news that the BBC has decided that the Met Office won’t be their main weather provider when the current contract ends has raised the question of where will the new provider get their information from. It’s important to understand that no weather forecasting organization, whether it is a National Met Service like the Met Office or an independent company, can provide a service without a forecast, and that it is the leading meteorological agencies, like the Met Office, that build and deliver those forecasts. So whoever the BBC chooses to deliver their weather services in future, you can be sure that Met Office observations and forecasts will continue to be at the heart of them. We are committed to driving forward the skill and usefulness of our forecasts and ensuring that all of us benefit from the advances the Met Office makes in the coming years with our new supercomputer.





Met Office in the Media – 7 August 2015

7 08 2015

Earth from space

An article published today makes a number of claims about Met Office weather and climate science.

It would be difficult to cover all the points raised in this blog, but here we look at the science and facts behind a few of the assertions.

The first decadal forecast issued in 2007

We did indeed publish the first groundbreaking decadal forecast in 2007. It had two headline statements:

  1. that half of all years after 2009 would be warmer globally than the record year at that time (1998) – This is doing well so far with two out of five years (2010 and 2014) warmer than 1998 and given current temperature levels, it’s likely this will be 3 out of 6 by the end of this year, consistent with our forecast for 2015
  2. that 2014 would be 0.3 °C ± 0.21 °C warmer than 2004 (giving a range of 0.09 °C to 0.51 °C) – WMO figures show the global temperature for 2014 was 0.13 °C higher than that in 2004; which is within the range of the forecast

Adjustments to global temperature data

The article says we adjust our temperature figures ‘without justifying why it is scientifically appropriate’. In fact, numerous peer-reviewed science papers from research centres across the world provide detailed explanations of how and why datasets are adjusted to ensure they are as accurate as possible. This is available for anyone to view and analyse.

The conclusion that the world has warmed is supported by independent analysis of global temperature data.

European heatwaves

We published a paper stating heatwaves like that seen across Europe in 2003 would become more frequent under climate change. Subsequent observations back up these conclusions; 2006 saw comparable heat in the UK, 2010 saw intense heat across eastern Europe, and there’s been a prolonged heatwave across much of Europe this year (although not in the UK).

Weather extremes

Met Office research supports climate research centres around the world which concludes we expect more extremes of heat and rainfall as the world continues to warm. The article says this ‘simply hasn’t happened’ but in fact, research shows there has been an increase in both. While here in the UK, we have also seen an increase in the number of temperature and rainfall records.

The article also states ‘the Met Office did all it could to claim the rain that caused last year’s exceptional flooding… was the worst ever recorded.’ We’ve done studies (here and here) of the exceptional rainfall in winter 2013/14., which across southern England was one of the, if not the most, exceptional periods for winter rainfall in around 250 years. Here’s a fuller research piece about the winter 2013/14 storms.

Greenland ice

The article says that we claimed Greenland ice would melt in future due to global warming. We did, and we were clear that it would take thousands of years to happen, not ‘any time soon’. Observations show Greenland has been losing 300 gigatonnes (1 gigatonne is 1000,000,000 tonnes) of ice a year over the last 12 years and research shows surface temperatures have clearly risen.

Other claims

A series of other claims are made in the article, mostly focusing on our forecasts over seasonal to decadal timescales. The Met Office is at the forefront of this pioneering area of research and we are increasing skill in this area.

According to standards set by the World Meteorological Organization the Met Office is ranked as the most accurate global met service in the world. We will continue our research in collaboration with our global scientific partners to improve this vital area of science.





Annual State of the Climate Report for 2014 published

16 07 2015

A report which looks at all the climate variables that can be measured for 2014 has been released today.

The annual ‘State of the Climate’ report has been published by the American Meteorological Society, presenting summaries for all so-called Essential Climate Variables (ECVs).

These include various types of greenhouse gases, temperatures throughout the atmosphere, ocean, and land, water cycle variables, ocean variables such as sea level and salinity, sea ice extent, permafrost temperatures and others. The majority of these reflect a planet that is continuing to warm.

The exceptional warmth of 2014 occurred against a backdrop of neutral to marginal El Niño conditions. Europe was especially warm and all land regions apart from North America showed above average frequency of warm extremes.

Annual average anomalies (difference to normal) for 2014 for surface temperature from the Met Office’s global temperature dataset, HadCRUT4 relative to a 1981-2010 climatology period.

Annual average anomalies (difference to normal) for 2014 for surface temperature from the Met Office’s global temperature dataset, HadCRUT4 relative to a 1981-2010 climatology period.

Over oceans, global sea surface temperatures and ocean heat content were also observed to be exceptionally warm and sea level exceptionally high.

The significant warmth is reflected strongly in regions of snow and ice. Arctic sea ice was well below average but above the exceptional lows seen in 2007, 2011 and 2012. Glacier volume is declining year on year – preliminary results for 2014 make it the 31st consecutive year of decline.

Long-lived greenhouse gases continued to increase, primarily owing to rising carbon dioxide (CO2) concentrations, in addition to methane (CH4), nitrous oxide (N2O) and other minor trace gases.

The Met Office’s Kate Willett, a lead chapter editor on the new report, said: “The comprehensive view of the different variables in the report enables a better understanding of the interconnectedness of our climate system.”

‘State of the Climate in 2014’ is the 25th consecutive instalment of the report, which is lead by scientists from NOAA’s National Centers for Environmental Information, along with 413 scientists from 58 countries.

Met Office scientist Kate Willett leads the Global Climate chapter and several other Met Office scientists contribute, using Met Office Hadley Centre climate data. All reports are freely available online.





Has there been a recent increase in UK weather records?

17 12 2014

There have been a striking number of temperature and rainfall records broken in recent years, according to an analysis by the Met Office which is published in the journal Weather.

The paper examines whether recent decades have seen an unusually high number of records broken in the UK. It looks at the number of records over time in the UK national statistics compiled by the Met Office’s National Climate Information Centre (NCIC).

Records were collated from long-running national and regional series of monthly, seasonal and annual temperature, rainfall, and sunshine.

The analysis counts records by decade and weights them according to their relative importance. More weight is given to national records compared to regions, and more weight to annual records compared to individual months.

The UK’s climate shows a large variability and this is bound to also be reflected in weather records. Even so, the analysis does reveal some interesting patterns.

Temperature records:

  • Since 2000, there have been 10 times as many hot records as cold records.
  • Taking into account the weighting, the period since 2000 accounts for two-thirds of all hot records in a national series from 1910, but only 3% of cold-records.
  • The longer Central England Temperature (CET) series, which dates back to 1659, reveals a similar trend – with seven out of a possible 17 records set since 2000 but no record cold periods.
  • The increase in hot records and decrease in cold records seen in recent decades is consistent with the long-term climate change signal. Seven of the warmest years in the UK series from 1910 have occurred since 2000.

Rainfall records:

  • Since 2000 there have been almost 10 times as many wet records as dry records.
  • Taking into account the weighting, the period since 2000 accounts for 45% of all wet records in a national series from 1910, but only 2% of dry records.
  • Remarkably, period since 2010 accounts for more wet records than any other decade – even though this only a 5 year period. The most prominent wet records in this period were winter 2013/2014 and April, June and year 2012.
  • The longer England & Wales Precipitation (EWP) series, which dates back to 1766, shows a similar trend – with six out of a possible 17 records set since 2000, but no record dry periods.
  • The large number of recent wet records may be indicative of trends in underlying rainfall patterns. We would expect an increase in heavy rainfall with climate change and this is an area of active research within the Met Office Hadley Centre.

Sunshine records:

  • In contrast with the other measures, there are no clear trends apparent in the sunshine records.

Exactly why we have seen these records is an ongoing area of research. You can see some discussion points related to this theme in a Met Office research paper on the drivers and impacts of our seasonal weather.

You can explore the Met Office’s climate data for the UK on our climate pages.





The 2013 global mean temperature

29 01 2014

In December 2013 we published an estimate of the global mean temperature up to the end of October 2013, based on an average of the three main global temperature datasets – Met Office and University of East Anglia (HadCRUT4), NOAA National Climatic Data Center (NOAA NCDC) and NASA Goddard Institute of Space Studies (NASA GISS).

The United Nations’ World Meteorological Organisation (WMO) and the IPCC’s provisional estimate global mean temperature for 2013 is 0.5 °C ± 0.1 °C above the long-term (1961-1990) average.

For HadCRUT4, the provisional estimate for the whole of 2013 is between 0.39 °C and 0.59 °C above the long-term (1961-1990) average of 14.0 °C, with a central estimate of 0.49 °C.

This means 2013 is in the top ten warmest years on record and we continue to see near record global temperatures like those which resulted in 2000-2009 being the warmest decade in the instrumental record.

As always the latest figure has generated interest in the media, which focuses on how it relates to previous forecasts from the Met Office.

The global mean temperature is just one of many indicators – including sea level rise, shrinking glaciers and reducing Arctic sea ice – that give even more confidence that the world is warming. Climate models are an invaluable tool in helping us to understand past changes and predict how temperatures may change in the future; they have provided overall good advice capturing and representing the warmer world we now live in.

We can see from the IPCC AR5 report figure below how global temperatures have risen since 1860 and how the latest provisional observational estimates still lie within the range of the forecast models. This figure also shows that, looking back over the entire observational record there are a number of occasions where the observations lie close to both the upper and lower bounds of the model simulations, so what we are seeing at the moment is nothing new.

Time series of global and annual-averaged surface temperature change from 1860 to 2012 showing results from two ensemble of climate models driven with natural forcings and human-induced changes in greenhouse gases and aerosols compared to observations of global mean temperature from three different datasets relative to 1880-1919. CMIP3 relates to the suite of climate models used in IPCC AR4 and CMIP5 those models used in IPCC AR5.*

Time series of global and annual-averaged surface temperature change from 1860 to 2012 showing results from two ensemble of climate models driven with natural forcings and human-induced changes in greenhouse gases and aerosols compared to observations of global mean temperature from three different datasets relative to 1880-1919. CMIP3 relates to the suite of climate models used in IPCC AR4 and CMIP5 those models used in IPCC AR5.*

So, why might the global mean temperature be different from forecasts? Well, we know that, due to the lack of long-term observing sites in polar latitudes, HadCRUT4 underestimates the contribution from Arctic warming which has accelerated in recent years.

There is also increasing scientific evidence that the current pause in surface warming is associated with natural variability in the global oceans, as they absorb heat from the atmosphere. Changes in the exchange of heat between the upper and deep ocean appear to have caused at least part of the pause in surface warming, and observations suggest that the Pacific Ocean may play a key role. You can find out more about the recent pause in warming here.

*Figure modified from Bindoff, N. L., P. A. Stott, K. M. AchutaRao, M. R. Allen, N. Gillett, D. Gutzler, K. Hansingo, G. Hegerl, Y. Hu, S. Jain, I. I. Mokhov, J. Overland, J. Perlwitz, R. Sebbari and X. Zhang, 2013: Detection and Attribution of Climate Change: from Global to Regional. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T. F., D. Qin, G.-K. Plattner, M. Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P. M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, in press.





Should climate models have predicted the pause?

27 09 2013

Media coverage today of the launch of the 5th Assessment Report of the IPCC has again said that global warming is “unequivocal” and that the pause in warming over the past 15 years is too short to reflect long-term trends.

Over recent days some commentators have criticised climate models for not predicting the pause. It’s good to see this being addressed, and so begin to clarify the difference between climate model projections and predictions.

We should not confuse climate prediction with climate change projection. Climate prediction is about saying what the state of the climate will be in the next few years, and it depends absolutely on knowing what the state of the climate is today. And that requires a vast number of high quality observations, of the atmosphere and especially of the ocean.

Whilst the last decade has seen a rapid increase in good observations of the surface and upper ocean, thanks to Argo floats, we have very few for the deep ocean. Without these requisite observations to initialise, i.e. set running, a climate prediction, it is impossible to have predicted the current pause, however good the climate models.

On the other hand, climate change projections are concerned with the long view; the impact of the large and powerful influences on our climate, such as greenhouse gases. Projections capture the role of these overwhelming influences on climate and its variability, rather than predict the current state of the variability itself.

The IPCC model simulations are projections and not predictions; in other words the models do not start from the state of the climate system today or even 10 years ago. There is no mileage in a story about models being ‘flawed’ because they did not predict the pause; it’s merely a misunderstanding of the science and the difference between a prediction and a projection.

As the IPCC states in line with our three papers on the pause, the deep ocean is likely a key player in the current pause, effectively ‘hiding’ heat from the surface. Climate model projections simulate such pauses, a few every hundred years lasting a decade or more; and they replicate the influence of the modes of natural climate variability, like the Pacific Decadal Oscillation (PDO) that we think is at the centre of the current pause.

The Daily Telegraph today also covers the science of the pause.

Critically there is ever more confidence that the world is warming as a result of human actions, and limiting climate change would require substantial and sustained reductions in emissions of carbon dioxide (CO2) and other greenhouse gases.








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