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Pacific Islands Environment Outlook - UNEP

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20<br />

STATE OF THE ENVIRONMENT<br />

425<br />

400<br />

375<br />

350<br />

Figure 1.7: Projected sea-level rise with adherence<br />

to Kyoto Protocol<br />

Atmospheric CO2 (ppm)<br />

450<br />

observed<br />

325<br />

300<br />

275<br />

predicted<br />

250<br />

1880 1990 2100<br />

Temperature (°C)<br />

1.2<br />

observed<br />

1.0<br />

0.8<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

-0.2<br />

-0.4<br />

-0.6<br />

-0.8<br />

1880<br />

Sea level change (cm)<br />

40<br />

observed<br />

30<br />

20<br />

10<br />

0<br />

-10<br />

-20<br />

-30<br />

1880<br />

predicted<br />

High Medium Low<br />

1990 2100<br />

predicted<br />

High Medium Low<br />

1990 2100<br />

Observed global mean atmospheric CO 2 concentrations,and temperature and<br />

sea-level changes to 1990 compared with projections to 2100 based on the<br />

IS92a emissions scenario to 2000, with a gradual application of the Kyoto<br />

Protocol to 2020 followed by a return of all greenhouse gas emissions to<br />

natural values from 2025 (Scenario 2). Projections of temperature and sea<br />

level are based on low, mid and high temperature sensitivity (1.5°C, 2.5°C and<br />

4.5°C) and mid-value ice-melt parameters, as in IPCC (1996). Observed data<br />

are as in IPCC (1996).<br />

the early 1990s. Tuvalu was hit by an average of three<br />

cyclones per decade between the 1940s and 1970s, but<br />

eight occurred in the 1980s (Nunn 1990).<br />

Trends forecast to 2010<br />

Observations of the past ten years have been further<br />

examined in recent studies of latent energy in the ocean<br />

system and regional impacts (Jones 1998; Jones et al.<br />

1999). It has been predicted (Jones 1998) that sea-level<br />

rise resulting from anthropogenic greenhouse gases<br />

already in the atmosphere has the potential to threaten<br />

all regions of the <strong>Pacific</strong>, particularly in areas where<br />

coastal impacts are currently marginal. The CSIRO<br />

models determined that sea-level rise caused by past<br />

human emissions of greenhouse gases would be of the<br />

order of 5–12 cm, peaking in 2020–25 (Jones 1998). Sealevel<br />

rise likely if the provisions of the Kyoto Protocol<br />

were adhered to, and if the world then ceased all<br />

anthropogenic greenhouse gas emissions after 2020,<br />

would range between 14 cm and 32 cm, peaking in<br />

2050–2100 (Figure 1.7).<br />

The prediction of regional impacts associated with<br />

climate change over the next ten years (Jones et al.<br />

1999) further reinforces the concerns raised during the<br />

last decade. Coastal areas will continue to experience<br />

impacts associated with ENSO variability, tropical<br />

cyclones and wave action. Tropical cyclones may<br />

become more intense, which would increase storm<br />

surge height. Current risks are therefore likely to<br />

persist and probably increase at a rate determined by<br />

sea-level rise (Jones et al. 1999).<br />

Conclusions<br />

Climate change and sea-level rise are expected to have<br />

profound effects on the <strong>Pacific</strong> islands and the issue is<br />

therefore expected to remain a priority for the region.<br />

PICs have experienced a range of impacts<br />

consistent with a changing climate. A general alteration<br />

occurred in the South <strong>Pacific</strong> climate<br />

from the mid-1970s, and the intensity of extreme<br />

events, such as the 1998 El Niño induced droughts in<br />

Fiji, PNG and the FSM which resulted in severe<br />

damage to food and export crops, has caused<br />

considerable concern.<br />

Based on current models and on the assumption that<br />

the Kyoto Protocol targets are met, coastal areas will<br />

continue to suffer phenomena resulting from ENSO<br />

variability, tropical cyclones and wave action. Tropical<br />

cyclones may become more intense, which would<br />

increase storm surge height.

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