Securing Multidisciplinary UndeRstanding and Prediction of Hiatus and Surge events (SMURPHS)

Lead Research Organisation: University of East Anglia
Department Name: Environmental Sciences

Abstract

Climate is currently changing mostly because of additional greenhouse gases, emitted through human activity, which are heating up the planet. Since future warming of climate is likely to cause damage to societies, governments are coordinating efforts to reduce greenhouse gas emissions to avoid these damaging consequences. However, despite the continuing rises in atmospheric greenhouse gas concentrations, the rate of warming of the Earth's surface has declined somewhat since the 1990s. While it is tempting to find a simple reason for this slowing (or "hiatus") in global surface warming, the climate system is extremely complex and there are many factors which can explain the lumps and bumps in the surface temperature record which also include increases (or "surges") in the rate of warming. The goal of our proposed programme of research is to understand much more fully how all the contributing factors can explain past hiatus and surge (H/S) events and this will ultimately help improve predictions of future climate change over the coming decades and far into the future.

The potential causes of H/S events includes: natural (so-called unforced) climate variability, due to complex interplay between the atmosphere, oceans and land; natural climate change due to volcanic eruptions or changes in the brightness of the sun; changes in how heat is moved into the deep oceans due to natural variations or human-caused factors; changes in emissions of gases such as methane due to human activity; limitations in the distribution of temperature observations, such that the hiatus is partly an artefact of imperfect observations. Rather than one single cause it is likely that H/S events are caused by a combination of factors. This is why a large team with a broad range of expertise is required to evaluate the different processes together. Our project, Securing Multidisciplinary UndeRstanding and Prediction of Hiatus and Surge events (SMURPHS) has brought together a comprehensive community of researchers from 9 UK institutes supported by 5 project partners including the Met Office who are experts in the atmosphere, the oceans and the land surface.

SMURPHS has 3 broad objectives, achieved through 6 research themes, which exploit theory, observations and detailed computer modelling. Objective 1 is to build a basic framework for interpreting H/S events in terms of energy moving between the atmosphere and ocean and to determine characteristics of and similarities between H/S events. Objective 2 is to understand mechanisms that could trigger H/S events and extend their length, considering both human and natural factors. Objective 3 is to assess whether H/S events can be predicted and what information is needed for near-term prediction of climate over coming decades which is important for how societies adapt to change. To meet these objectives scientists from a range of different disciplines will work on each of these possibilities and communicate their findings across the team. SMURPHS will produce a wide-ranging synthesis of its results.

SMURPHS will have many beneficiaries. Beyond the global scientific community, improved understanding of H/S events is important at national and international levels for designing policies to control future greenhouse gas emissions and for effective adaptation to climate change. Intergovernmental Panel on Climate Change (IPCC) assessments have deeply influenced climate policy development at the international and national levels. Scientists involved in SMURPHS have contributed significantly to previous IPCC reports, and SMURPHS science and scientists would contribute significantly to future such assessments.

Planned Impact

1. The World Climate Research Program (WCRP) 6th Climate Model Intercomparison (CMIP6) Committee, participating climate research centres, and the international research community will benefit from new radiative forcing scenarios with quantified uncertainties promoted through WCRP/CMIP6 planning meetings. SMURPHS will contribute directly to the CMIP6 plans and host relevant meetings during the project. The SMURPHS webpage will provide the latest information to the international modelling centres and a contact list will be drawn up for provision of regular notifications.

2. International policy makers representing governments in the United Nations Framework Convention on Climate Change (UNFCCC) negotiations; National policy makers in the Department of Energy and Climate Change (DECC) and the Committee for Climate Change (CCC) and European Union counterparts; and International and national non-governmental organisations (NGOs) will benefit from improved understanding of decadal variability in global mean surface temperature rise and of the relationship between short term and longer term trends.

Two critical issues for these groups are: (i) implications of the recent hiatus for long term climate change (mitigation policy), and (ii) constraints on the rate of climate change over the next few decades (adaptation policy). We will organize two international workshops to synthesize research findings and bring together additional international perspectives to provide an overall assessment. Key outputs will be two assessment papers for input to the Sixth Assessment Report of the IPCC (AR6). Lack of complete understanding of the hiatus was a major gap in IPCC AR5, which SMURPHS will address directly. As part of these workshops, a discussion session will be held with invited policymakers from DECC and other government departments to explore the implications of our findings. We also plan to hold a side event on historic temperature trends at a UNFCCC Conference of the Parties (expected in December 2017).

3. The Met Office (MO) has strategic plans to improve near term prediction of climate change and with DECC/DEFRA and CCC will produce revised mitigation pathways to avoid dangerous climate change. The MO will benefit from improved quantification of past radiative forcing and understanding of variability in global-mean surface temperature rise, resulting in improved models and predictions. A close working relationship with the MO is established and a coordinated programme of work has been designed. MO colleagues will attend project meetings and SMURPHS PDRAs will spend time based at the MO. The Met Office Academic Partnership involving the Universities of Exeter, Leeds, Oxford and Reading provides an additional mechanism for collaboration.

4. The general public and the media. SMURPHS will benefit the interested public by enabling clearer and more precise explanations of the hiatus and implications for long-term climate change. Several media articles used poor understanding of the hiatus to challenge the Government's emission reduction targets in 2013. In response the Science Media Centre (SMC) prepared a briefing note on the hiatus with significant contributions from Forster, Sutton, Allan and Hawkins. We will work with the SMC to update this briefing note at the end of the project, and will discuss holding a briefing meeting for interested journalists. Shine is very active in ongoing Royal Society efforts to explain climate change science to a wide audience via a number of activities, and expects to continue to be so during SMURPHS. Outputs from the project will be written up in a form that is accessible for the interested general public on Hawkins' climate-lab-book blog which also provides a mechanism for public engagement and feedback. Key findings will be communicated on Twitter. All PIs and Co-Is have press experience and engagement with the media will continue throughout the project.

Publications

10 25 50
 
Description Our estimates of global temperature change during the period from 1850 to present have been improved. Improvements have been made in a number of ways, such as increasing the number of observations used, making use of improved corrections for measurement biases developed by the Met Office, and addressing the bias that arises from poorly observed regions tending to be those that have recently warmed the most. The new global temperature dataset version HadCRUT5 indicates that about 18% more warming has occurred since 1850 than we had previously estimated, bringing us to about 1.2C above pre-industrial levels by 2020. Furthermore, the slowdown (sometimes called the 'hiatus') in the rate of warming during the period 1998 to 2012 was probably not as large as we previously thought.
Exploitation Route The new global temperature dataset and findings have been shared publicly and will be used by the academic community for making better estimates of the amount of global warming attributed to human activities, better estimates of climate sensitivity, and updated estimates of the remaining carbon budget that is consistent with the goals of the Paris climate agreement.
Sectors Energy

Environment

Government

Democracy and Justice

 
Description The updated global temperature record, HadCRUT5, is being used in the next IPCC assessment, the sixth assessment report (AR6). This is significant because the estimated warming since pre-industrial is considerably higher than we previously estimated. Warming to date is now around 1.2 C, implying that we are closer (by 0.1 to 0.2 C) to the Paris climate agreement goals. Our impact has therefore been on evaluating progress towards international policy goals, via our influence on the IPCC's assessment.
First Year Of Impact 2021
Sector Government, Democracy and Justice
Impact Types Policy & public services

 
Title CRUTEM.5.0.0.0: Climatic Research Unit (CRU) gridded near-surface air temperature anomalies over land 
Description CRUTEM (Climatic Research Unit TEMperature) is a gridded dataset of global historical near-surface air temperature anomalies over land at a monthly timescale. It is a collaborative product of the Climatic Research Unit at the University of East Anglia, the Met Office Hadley Centre and the National Centre for Atmospheric Science. CRUTEM also contributes the land air temperature station data to the global (land and ocean) temperature dataset called HadCRUT. CRUTEM5 is the fifth major version of the dataset, covering the time period from 1850, with a spatial resolution of 5° latitude by 5° longitude and a monthly-mean time resolution. The gridded temperature anomaly fields are based on a compilation of monthly-mean temperature observational records from weather stations. This compilation contains 10639 station records, but only 7983 records had the necessary coverage to be used for producing the gridded dataset. Anomalies are differences from average conditions in the 1961-1990 period. Hemispheric and global mean time series of land air temperature anomalies are also provided. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact It is being used in the next IPCC assessment as a record of global temperature changes over land. 
URL https://catalogue.ceda.ac.uk/uuid/901f576dacae4e049630ab879d6fb476
 
Title CRUTEM4.5 and HadCRUT4.5 
Description CRUTEM is a gridded dataset of global historical near-surface air temperature anomalies over land. Data are available for each month from January 1850 to present, on a 5 degree grid. The dataset is a collaborative product of the Met Office Hadley Centre and the Climatic Research Unit at the University of East Anglia. The annual update to produce version CRUTEM4.5 was released in 2016 was partially supported by NCAS and partially supported by SMURPHS. The additional data sources that NCAS and SMURPHS support allowed us to add in CRUTEM4.5 are described here: http://www.metoffice.gov.uk/hadobs/crutem4/data/CRUTEM.4.5.0.0_release_notes.html CRUTEM forms the land component of the global land and marine temperature record HadCRUT. CRUTEM4.5 contributed the land component to the 2016 update of the combined dataset, HadCRUT4.5. 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
Impact The CRUTEM4.5 and HadCRUT4.5 global temperature datasets contributed to the WMO's confirmation that 2016 was hottest on record. https://public.wmo.int/en/media/press-release/wmo-confirms-2016-hottest-year-record-about-11%C2%B0c-above-pre-industrial-era 
URL https://crudata.uea.ac.uk/cru/data/temperature/
 
Title CRUTEM4.6 and HadCRUT4.6 global temperature data 
Description CRUTEM is a gridded dataset of global historical near-surface air temperature anomalies over land. Data are available for each month from January 1850 to present, on a 5 degree grid. The dataset is a collaborative product of the Met Office Hadley Centre and the Climatic Research Unit at the University of East Anglia. The annual update to produce version CRUTEM4.6 was released in 2017 was partially supported by NCAS and partially supported by SMURPHS. The additional data sources that NCAS and SMURPHS support allowed us to add in CRUTEM4.6 are described here: http://www.metoffice.gov.uk/hadobs/crutem4/data/CRUTEM.4.6.0.0_release_notes.html CRUTEM forms the land component of the global land and marine temperature record HadCRUT. CRUTEM4.5 contributed the land component to the 2016 update of the combined dataset, HadCRUT4.5. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact The CRUTEM4.6 and HadCRUT4.6 global temperature datasets contributed to the WMO's confirmation that the years 2015-2019 were the five warmest years on record. https://public.wmo.int/en/media/press-release/2019-concludes-decade-of-exceptional-global-heat-and-high-impact-weather 
URL https://crudata.uea.ac.uk/cru/data/temperature/
 
Title HadCRUT.5.0.0.0: Ensemble near-surface temperature anomaly grids and time series 
Description HadCRUT5 (Met Office Hadley Centre/Climatic Research Unit global surface temperature anomalies, version 5) is a gridded dataset of global historical near-surface air temperature anomalies since the year 1850. It has been developed and maintained by the Met Office Hadley Centre and University of East Anglia Climatic Research Unit. Air temperature information over land is derived from CRUTEM5 monthly average meteorological station temperature series, an expanded compilation of station series with revised quality control methods. Temperatures over ocean are derived from the HadSST4 sea-surface temperature dataset, including revised assessments of instrumental biases. Temperature data are presented as monthly average near-surface temperature anomalies, relative to the 1961-1990 period, on a regular 5° latitude by 5° longitude grid from 1850 to 2018, with derived global and hemispheric time series. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact HadCRUT5 is being used in the IPCC's sixth assessment report as a record of global temperature change. 
URL https://catalogue.ceda.ac.uk/uuid/b9698c5ecf754b1d981728c37d3a9f02