Natural England - Yorkshire and the Humber climate change projections
Yorkshire and the Humber climate change projections
A number of comparisons have been carried out for the region for the 2050s using the medium emissions scenario for the United Kingdom Climate Projections 2009 (UKCP09) and medium high for United Kingdom Climate Impacts Programme 2002 (UKCIP02). Thus, the UKCP 2009 projections are for a somewhat less severe perturbation to the climate system. For UKCP 2009, unless stated otherwise, the median (or 50 percentile) estimate has been used: this can be interpreted as the value with a 50:50, or even, chance of being exceeded.
Overall, it is found that the UKCP 2009 projections are broadly similar in direction and magnitude of change for changes in means of climate variables such as temperature and rainfall. However, in some cases (e.g. for droughts, heat-waves and extreme heavy rainfall) UKCP 2009 suggests substantially larger future changes.
| Climatic condition | UKCIP02 scenario | UKCP09 scenario |
|---|---|---|
| Average daily temperatures | Average daily temperatures will increase across the region throughout all seasons. The greatest net increases will be in summer of around 2.1°C to 2.5°C and the lowest in winter of around 1.3°C to 1.5 °C. | estimates are for around a 2.3 °C increase in summer, but with a 10% chance of rising as much as 3.9 °C. The lowest seasonal increase is in winter, at around 2.2 °C, but with 10% chance of as large a change as 3.4 °C. So, UKCP09 suggests similar increases in temperature, with somewhat greater warming in winter |
| Extreme hot temperatures | With an expected increase of up to around 3.4°C in extreme hot temperatures we can more regularly expect the summer daily average temperatures to reach around 34°C in many parts of the region, especially for the more southern parts of the region | shows expected rises in extreme temperatures around 3.2 °C, but with a 10% chance of being as high as 4.9 °C. So, UKCP09 suggests similar increases in the extreme hot temperatures |
| Hot days | suggests a greater tendency for daily temperatures to exceed the 28°C threshold, with some areas of the region experiencing over 6 days in the summer where this threshold is exceeded | projects the number of days exceeding 28°C to reach ten days, with a 10% chance of reaching 25 days. Currently, only the south of the region experiences 1 day per year on average exceeding 28 °C. So, UKCP09 suggests a significantly greater tendency than UKCIP02 for occurrence of very hot days |
| Frost days | suggested that across the region there will be between a 35% and 50% reduction in the number of frost days per year | suggests frost days are expected to reduce by between 46 and 60%, but with a 10% chance of warming to such an extent that they are reduced by 80%, resulting in only some 10 days or fewer in much of the region. So, UKCP09 suggests somewhat more winter warming than UKCIP02 |
| Rainfall | suggests the region should expect greater seasonal variation of rainfall with increases in winter rainfall combined with summer decreases | suggests little change in annual rainfall, but with increased seasonality. Winter rainfall is set to rise by 11%, with a 10% chance of rising by 24%. Summer rainfall is projected to reduce by 18%, with a 10% chance of a reduction of 36%. This winter increase is very similar to UKCIP02, but the summer decrease is rather more severe, as UKCIP02 suggested a reduction of only some 10% |
| Dry spells | suggested the number of occurrences of 10 and 20 consecutive days without rainfall would increase by up to 3 additional occurrences per year | dry spells of 10 days are expected to increase with 50% probability from an average of around 4 spells per year to between 5 and 6. There is a 10% chance of an increase from 4 spells to up to 9, which would constitute severe drought conditions. So, the UKCP09 projections are for rather more severe drying, essentially in the summer |
| Extreme rainfall | The heavy rainfall events over areas such as the North Yorkshire Moors were projected to increase by UKCIP02, with the 50% AEP 1-day rainfall event increasing by some 6.5%. In other areas little change, or in some cases reductions had been suggested | suggests somewhat larger increases in the 1-day 50% AEP events, in the range of 8 to 11 %, mostly caused by increased frequency of winter rainfall. Changes in hourly rainfall are smaller, but it should be noted that these are rather more difficult to interpret and less reliable. This is because the only climate change signal which has been applied is from climate models with information at the daily scale, so little account is made of any impact of changes in short duration events such as thunderstorms |
| Sea level rise | The previous guidance from central government recommends allowances to be made in the design of coastal protection and sea defence works of around 4mm per year up to 2025 and then 8.5mm per year up to 2055. | marine projections suggest some 2.6 mm per year rise up to 2020, increasing to 3.4 mm up to 2050. These are within the previous guidance. In terms of total sea level rise, these equate to some 18 cm by 2050, but with a 5% chance of reaching 22 cm. This is somewhat lower than the values calculated using the previous ‘design’ guidance values but nonetheless remains an important climate change to which we will need to adapt. |
