Anglia Climatic Research Unit Research Articles

Agroecological-based modeling of meteorological drought at 12-month time scale in the Western Cape Province of South Africa

To mitigate the effects of drought in water-stressed agro-ecological zones (AEZs), it is crucial to implement efficient monitoring of drought characteristics and establish proactive water-use strategies. The Western Cape (WC) province is being confronted with an escalating threat of diminished water availability due to unsustainable human activities. The objective of this study was to assess the spatio-temporal characteristics of meteorological drought within a 12-month timescale in the WC province of South Africa spanning from 1980 to 2020. The University of East Anglia's Climate Research Unit provided precipitation datasets from fifteen stations across the six AEZs of the WC province. These datasets were processed using the Standardized Precipitation Index (SPI). The Mann–Kendall (M–K) test was used to analyze the precipitation trend and SPI values at a significance level of p < 0.05. The results indicated substantial negative trends in annual precipitation across all AEZs. An examination of seasonal precipitation patterns revealed a rise in summer precipitation in subtropical cool-arid regions and subtropical warm semi-arid regions, with increases of 0.4 and 0.2 mm/year, respectively. Conversely, the overall annual precipitation trend fell by -1.0 mm/year in both AEZs. The SPI values consistently fell within the range of -2 to 0 in the subtropical warm-arid, subtropical cool-arid, and subtropical cool-arid zones. Conversely, the SPI values were consistently positive in the subtropical warm-arid, subtropical cool-humid, and subtropical warm-humid zones. This finding suggests that there will be persistent drought conditions that will affect agricultural production, surface flows in rivers, and groundwater levels across the WC province.

Economic effects of climate change on agricultural production and productivity in Latin America and the Caribbean (LAC)

AbstractClimate projections indicate that temperatures in Latin America and the Caribbean (LAC) will rise by between 1.6 °C and 4 °C by the end of the century while changes in precipitation levels are expected to vary significantly across the region. This article estimates the impact of climate change on total factor productivity (TFP) and production. It combines data from the University of East Anglia's Climatic Research Unit (CRU), the Intergovernmental Panel on Climate Change (IPCC), and the Food and Agriculture Organization (FAO) on 28 LAC countries for a 54‐year period (1961–2014) in order to inform policy makers of the cost of output losses in the absence of viable climate adaptation strategies. We use estimates of a random‐parameter stochastic production frontier (SPF) model specification to capture heterogeneity in technology and partial output elasticities across countries and unobserved environmental characteristics. Results show that change in output is mainly driven by an average annual TFP growth rate of .95%. Climate change induces significant reductions (9.03–12.7%) in productivity over the 2015–2050 period. In terms of output, these losses range from USD $14.7 to $31.4 billion dollars in the LAC region, depending on the scenario and the discount rate used.

Using MODIS land surface temperatures and the Crocus snow model to understand the warm bias of ERA-Interim reanalyses at the surface in Antarctica

Abstract. Moderate-Resolution Imaging spectroradiometer (MODIS) land surface temperatures in Antarctica were processed in order to produce a gridded data set at 25 km resolution, spanning the period 2000–2011 at an hourly time step. The Aqua and Terra orbits and MODIS swath width, combined with frequent clear-sky conditions, lead to very high availability of quality-controlled observations: on average, hourly data are available 14 h per day at the grid points around the South Pole and more than 9 h over a large area of the Antarctic Plateau. Processed MODIS land surface temperatures, referred to hereinafter as MODIS Ts values, were compared with in situ hourly measurements of surface temperature collected over the entirety of the year 2009 by seven stations from the Baseline Surface Radiation Network (BSRN) and automatic weather stations (AWSs). In spite of an occasional failure in the detection of clouds, MODIS Ts values exhibit a good performance, with a bias ranging from −1.8 to 0.1 °C and errors ranging from 2.2 to 4.8 °C root mean square at the five stations located on the plateau. These results show that MODIS Ts values can be used as a precise and accurate reference to test other surface temperature data sets. Here, we evaluate the performance of surface temperature in the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis known as ERA-Interim reanalysis. During conditions detected as cloud free by MODIS, ERA-Interim shows a widespread warm bias in Antarctica in every season, ranging from +3 to +6 °C on the plateau. This confirms a recent study which showed that the largest discrepancies in 2 m air temperature between ERA-Interim and the global temperature data set HadCRUT4 compiled by the Met Office Hadley Centre and the University of East Anglia's Climatic Research Unit occur in Antarctica. A comparison with in situ surface temperature shows that this bias is not strictly limited to clear-sky conditions. A detailed comparison with stand-alone simulations by the Crocus snowpack model, forced by ERA-Interim, and with the ERA-Interim/land simulations, shows that the warm bias may be due primarily to an overestimation of the surface turbulent fluxes in very stable conditions. Numerical experiments with Crocus show that a small change in the parameterization of the effects of stability on the surface exchange coefficients can significantly impact the snow surface temperature. The ERA-Interim warm bias appears to be likely due to an overestimation of the surface exchange coefficients under very stable conditions.

The legacy of climategate: revitalizing or undermining climate science and policy?

AbstractThe release of emails from a server at the University of East Anglia's Climate Research Unit (CRU) in November 2009 and the following climategate controversy have become a topic for interpretation in the social sciences. This article picks out some of the most visible social science comments on the affair for discussion. These comments are compared to an account of what can be seen as problematic practices by climate scientists. There is general agreement in these comments that climate science needs more openness and transparency. But when evaluating climategate a variety of responses is seen, ranging from the apologetic to the highly critical, even condemning the practices in question. It is argued that reluctance to critically examine the climategate affair, including suspect practices of scientists, has to do with the nature of the debate which is highly politicized. A call is made for more reflection on this case which should not be closed off because of political expediency. WIREs Clim Change 2012 doi: 10.1002/wcc.166This article is categorized under: Social Status of Climate Change Knowledge &gt; Knowledge and Practice

The phenology of Rubus fruticosus in Ireland: herbarium specimens provide evidence for the response of phenophases to temperature, with implications for climate warming

To date, phenological research has provided evidence that climate warming is impacting both animals and plants, evidenced by the altered timing of phenophases. Much of the evidence supporting these findings has been provided by analysis of historic records and present-day fieldwork; herbaria have been identified recently as an alternative source of phenological data. Here, we used Rubus specimens to evaluate herbaria as potential sources of phenological data for use in climate change research and to develop the methodology for using herbaria specimens in phenological studies. Data relevant to phenology (collection date) were recorded from the information cards of over 600 herbarium specimens at Ireland's National Herbarium in Dublin. Each specimen was assigned a score (0-5) corresponding to its phenophase. Temperature data for the study period (1852 - 2007) were obtained from the University of East Anglia's Climate Research Unit (CRU); relationships between temperature and the dates of first flower, full flower, first fruit and full fruit were assessed using weighted linear regression. Of the five species of Rubus examined in this study, specimens of only one (R. fruticosus) were sufficiently abundant to yield statistically significant relationships with temperature. The results revealed a trend towards earlier dates of first flower, full flower and first fruit phenophases with increasing temperature. Through its multi-phenophase approach, this research serves to extend the most recent work-which validated the use of herbaria through use of a single phenophase-to confirm herbarium-based research as a robust methodology for use in future phenological studies.

Around the World

In science news around the world this week, scientists in Germany have detected what they think is a new virus in cattle, scientists say there's nothing new in the 5000 new e-mails hackers have released from the University of East Anglia's Climate Research Unit, NASA's Mars Science Laboratory has been successfully launched, and a study of a vaginal gel laced with an anti-HIV drug has failed to show any benefit.

Temperature and Malaria Trends in Highland East Africa

There has been considerable debate on the existence of trends in climate in the highlands of East Africa and hypotheses about their potential effect on the trends in malaria in the region. We apply a new robust trend test to mean temperature time series data from three editions of the University of East Anglia's Climatic Research Unit database (CRU TS) for several relevant locations. We find significant trends in the data extracted from newer editions of the database but not in the older version for periods ending in 1996. The trends in the newer data are even more significant when post-1996 data are added to the samples. We also test for trends in the data from the Kericho meteorological station prepared by Omumbo et al. We find no significant trend in the 1979-1995 period but a highly significant trend in the full 1979-2009 sample. However, although the malaria cases observed at Kericho, Kenya rose during a period of resurgent epidemics (1994-2002) they have since returned to a low level. A large assembly of parasite rate surveys from the region, stratified by altitude, show that this decrease in malaria prevalence is not limited to Kericho.

The Perversion of Scientific Evidence for Policy Advocacy: A Perspective on Avery 2010

The claims of scientific misconduct surrounding the pandemic influenza event in 2009 and the furor surrounding purported scientific manipulation at the University of East Anglia's Climate Research Unit were used as grounds in Avery's 2010 paper to ostensibly criticize how science is corrupted by the need to support particular political or ethical perspectives and, implicitly, that such perspectives are either lacking in evidence, or that such evidence is distorted or suppressed to maintain the politically correct interpretation. However, this rejoinder to Avery's paper demonstrates unambiguously that both unbalanced interpretation and one-sided presentation of opinion as evidence in support of these claims is in fact a thinly disguised attack on two issues that are contentious to certain vested interests. Having written the original paper on which Avery 2010 is based for a think tank well known for its opposition on ideological grounds to both environmental legislation and anthropogenic global warming, and for which some funding was received, Avery undermines his own arguments by appearing to embody the very problem he seeks to reveal. This rejoinder details why that seems to be the case.

Media mea culpa

Media mea culpa

Ensuring Integrity in Science

Hacked Electronic Records of Climate Scientists at the University of East Anglia's Climate Research Unit (UEA/CRU) led to worldwide publicity during the December 2009 Copenhagen climate change convention. UEA is conducting a formal investigation to determine whether UEA scientists manipulated or suppressed data or otherwise acted unprofessionally. My reading of the vast scientific literature on climate change is that our understanding is undiminished by this incident; but it has raised concern about the standards of science and has damaged public trust in what scientists do.

Northern Hemisphere freezing/thawing index variations over the twentieth century

AbstractChanges in the ground thermal regime in high‐latitude cold regions have important consequences for surface and subsurface hydrology, the surface energy and moisture balance, carbon exchange, as well as ecosystem diversity and productivity. However, assessing these changes, particularly in light of significant atmospheric and terrestrial changes in recent decades, remains a challenge owing to data sparseness and discontinuous observations. The annual freezing and thawing index can be useful in evaluating permafrost and seasonally frozen ground distribution, has important engineering applications, and is a useful indicator of high‐latitude climate change. The freezing/thawing index is generally defined based on daily observations, which are not readily available for many high‐latitude locations. We thus employ monthly air temperatures, and provide an assessment of the validity of this approach. On the basis of a comprehensive relative error (RE) evaluation we find that our methodology introduces errors of less than 5% for most high‐latitude land areas, and works well in many midlatitude regions as well. We evaluate a suite of gridded monthly temperature datasets and select the University of East Anglia's Climatic Research Unit (CRU) temperature product, available for 1901–2002. We are thus able to provide a continuous long‐term 25 km × 25 km gridded Northern Hemisphere freezing/thawing index. Long‐term climatologies of the freezing/thawing index delineate the cold regions of the Northern Hemisphere, as well as areas of seasonally frozen ground and permafrost. Objective trend analysis indicates that in recent decades, no significant changes have occurred in Russian permafrost regions; however, seasonally frozen ground areas are experiencing significant warming trends. Over North America, Canadian and Alaskan permafrost regions are experiencing a decrease in freezing index during the cold season, while coastal areas and eastern Canada are seeing significant increase in warm season thawing index. Copyright © 2006 Royal Meteorological Society.

Potential Impacts of Climatic Change and of Sea‐Level Rise on the Yields of Aquifer, River and Reservoir Sources

ABSTRACTUsing regional statistics of daily rainfall, a simple water‐balance model was employed to generate runoff sequences with which to simulate the yield/storage behaviour of reservoirs in south‐east England, in north‐west England, and North Wales. Similarly sequences of recharge to an unconfined aquifer in eastern England were the basis of deriving its yield/storage behaviour. Then, taking scenarios of the year 2030 rainfall and evaporation, provided by the University of East Anglia's Climatic Research Unit, reductions in yield were calculated to be 5–15% below present‐day values. For direct supply reservoirs, greater percentage reductions in yield were found to apply to the south‐east region, as compared to the north‐west. The results from the aquifer example are interpreted on a novel basis which allows an immediate comparison with the surface reservoir examples.Coastal sea‐water intrusion was modelled for three common geological conditions (i) the Grimsby Chalk (confined), (ii) the Brighton Chalk (unconfined), and (hi) the Otter Valley Sandstone (unconfined). In all three cases the effect of a possible 0.6 m rise in mean sea level was shown to have only a marginal effect on sustainable yields, which reduced by about 1.5%.Estuarine fresh‐salt water interfaces are important to the abstraction regime of freshwater intakes in the lower reaches of rivers. The effect of a 0.6‐m sea‐level rise on the saline interface location at high tide was evaluated by hydrodynamic computational models. Only a minor inland shin of the interface was found, less man 800 m in the Thames tideway and less than 500 m in the Lune estuary. The Severn estuary is exceptional in having its saline interface move 3.5 km landwards for the same 0.6‐m rise in mean sea level.