Designing for Climate Change
Representative Concentration Pathways (RCP) ratings indicate predicted rainfall based on the anticipated affects of climate change.
Our online calculators provide rainfall intensity values from E1.AS1, Appendix A, by selecting the regional location and apply a RCP rating. Use an apropriate RCP level to ensure design calculations account for current and future rainfall scenarios.
The pay-per-use HIRDS tool from NIWA provides figures for historical rainfall intensities and predicted rainfall based on RCP levels for sepcific sites.
The increased rainfall intensity in a worst-case scenario is typically 11 – 13% higher than historical levels, mostly occurring under the least intense (RCP 2.6) value.
RCP Level Descriptions
| Rating | Description |
|---|---|
| RCP 2.6 | Assumes stringent, immediate action, with greenhouse gases peaking around 2020 and declining sharply, aiming to keep global warming below 2°C. |
| RCP4.5 | An intermediate scenario where CO2 levels peak by 2040, then decline due to the decreased availability of fossil fuels. |
| RCP 6.0 | A stabilisation scenario, where CO2 emissions peak around 2080, then decline with the deployment of various technologies and strategies. |
| RCP 8.5 | Worst-Case scenario where CO2 emissions continue to rise throughout the 21st century. Thought by some to be based on an overestimation of projected coal outputs. |
Example of RCP Values for Randomly Selected Locations with Historic Values quoted from E1/AS1
| Location | Historic | RCP 2.6 | RCP 4.5 | RCP 6.0 | RCP 8.5 |
|---|---|---|---|---|---|
| Whangarei | 140 | 151 | 153 | 155 | 157 |
| Auckland Central | 127 | 137 | 139 | 141 | 142 |
| Tauranga | 145 | 157 | 158 | 161 | 162 |
| Kapiti | 103 | 111 | 113 | 114 | 115 |
| Christchurch | 62 | 67 | 68 | 69 | 69 |
| Dunedin | 73 | 79 | 80 | 81 | 82 |
| Queenstown | 53 | 57 | 58 | 59 | 59 |
| Huntly | 125 | 135 | 137 | 138 | 140 |
| Nelson | 107 | 116 | 117 | 118 | 120 |
Use our online caculators or visit NIWA pay-per-use HIRDS-tool to get the corresponding values for your location.
Example of increasing ARI figures Using RCP Values from Random Locations
Use our online calculators or visit NIWA pay-per-use HIRDS-tool to get the corresponding values for your location.
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