Selamatkan bumi kita

Oleh Siti Mariam Md. Zain

BUMI umpama rumah besar bagi segala hidupan bukan sahaja manusia tetapi serangga, haiwan dan tumbuh-tumbuhan. Bezanya manusia dan hidupan-hidupan lain ialah kita dianugerahkan akal dan kebijaksanaan.
Namun akal dan kebijaksanaan itu sering disalahgunakan. Mungkin dari satu segi, ia tidak nampak salah, tetapi kita harus sedar bahawa setiap tindakan yang diambil perlu memikirkan kesan baik dan buruk kepada hidupan lain juga.
Inilah sebenarnya fungsi manusia. Memberi yang terbaik kepada seluruh hidupan bumi agar sama-sama dapat berasa nikmat yang lebih sempurna. Tindakan memusnahkan alam sewenang- wenangnya jelas bukan tindakan bijak.
Malangnya, peranan ini sering jatuh ke tempat terakhir selagi kesan itu tidak dirasai sendiri. Lihat sahaja di rumah- rumah kita betapa tenaga elektrik secara lumrahnya dibazirkan begitu sahaja. Lampu yang dipasang tidak setakat penuh di dalam rumah tetapi juga melimpah ruah ke luar rumah. Penggunaan pendingin udara tanpa kawalan terus menjadi penyumbang utama kepada penipisan ozon akibat pengeluaran gas chlorofluorocarbon (CFC).
Itu belum termasuk faktor kenderaan. Di ibu negara dan bandar-bandar besar lain, isu kesesakan lalu lintas seolah-olah telah menjadi perkara biasa. Natijahnya ialah semakin banyak karbon dioksida yang dilepaskan.
Lapisan ozon di stratosfera yang semakin nipis membolehkan sinaran ultra ungu sampai ke permukaan bumi lalu menyebabkan suhu meningkat. Selain pendingin udara, CFC juga dihasilkan oleh penyembur aerosol, penggunaan baja organik berterusan dalam pertanian (menghasilkan nitrogen oksida), pembakaran bahan api fosil (nitrogen dioksida), ujian senjata nuklear, peperangan yang menggunakan bahan letupan dan penggunaan jet supersonik
Keadaan ini bukan sahaja mempengaruhi perubahan iklim, tetapi juga penyakit seperti katarak mata dan kanser kulit, mengurangkan proses fotosintesis tumbuh-tumbuhan, memusnahkan sel mikro organisma pada tumbuh-tumbuhan dan binatang, membunuh sistem pelalian manusia dan binatang serta banyak lagi kesan negatif.
Peningkatan suhu menyebabkan pencairan ais atau glasier seterusnya menyaksikan peningkatan aras laut berikutan isi padu air laut yang bertambah. Apabila air laut bertambah, kawasan-kawasan rendah akan mengalami banjir. Bermakna banjir tidak lagi berlaku di negara-negara yang sering dilanda banjir sahaja tetapi juga tempat-tempat lain.
Dan apa yang kita saksikan hari ini adalah fenomena yang terhasil daripada sikap dan tindakan manusia itu sendiri. Jika kesedaran ini muncul sejak lama dulu, apa yang dialami mungkin dapat dielakkan atau kesannya dikurangkan. Perubahan mendadak ini menyedarkan manusia betapa perlunya kita bersama-sama menjaga alam sekitar.
Malah dalam satu undian yang dilakukan di Switzerland baru-baru ini mendapati lebih 80 peratus rakyat negara itu bersedia mengurangkan penggunaan kereta masing-masing sebagai alternatif pencegahan perubahan cuaca ketara.
Undian yang dibuat menerusi akhbar Sonntagsblick itu mendapati 67 peratus pengundi percaya manusia hanya tahu menyalahkan apa yang berlaku dan 63 peratus bersetuju bahawa perubahan cuaca mengancam survival manusia.
Secara keseluruhan, 88 peratus berkata, mereka bersedia menyumbang secara peribadi untuk mengurangkan pengeluaran gas karbon dioksida yang merupakan punca utama pemanasan atmosfera bumi dan merosakkan iklim.
Undian juga mendedahkan sebahagian besar rakyat Swiss mahu pihak berkuasa mengambil tindakan sewajarnya. Mereka mendapati kerajaan hanya mengambil langkah yang terlalu sedikit bagi menangani masalah itu setakat ini.
Lebih 80 peratus juga menyokong lebih banyak cukai kenderaan dikenakan ke atas kenderaan yang boleh menampung jumlah minyak yang lebih banyak, begitu juga ke atas pengangkutan awam dan mempertingkatkan kemampuan kenderaan lama agar lebih mesra alam sebagaimana pemulihan yang dilakukan terhadap bangunan.
Dua pertiga daripada tinjauan yang dibuat oleh Institut Isomar membabitkan 1,001 orang antara 31 Januari hingga 3 Februari lalu itu juga mahu pihak berkuasa mewajibkan penjimatan tenaga ke atas lampu dan peralatan elektrik lain.
Minggu lalu, saintis Pertubuhan Bangsa-Bangsa Bersatu (PBB) telah memberi amaran berkaitan peningkatan pemanasan global dan bagaimana manusia perlu memainkan peranan mereka bagi mengurangkan perubahan iklim.
Pencairan ais luar biasa dan salji kering yang berlaku di Alps beberapa bulan lalu menimbulkan keadaan panik dan ketakutan di Switzerland kesan daripada perubahan cuaca yang ketara kebelakangan ini.
Setiausaha Agung PBB, Ban Ki-moon berkata, negara-negara yang kurang mengambil berat tentang kesan pemanasan global yang sedang melanda dunia bakal menerima kesan yang lebih besar berbanding negara lain.
Tidak menentu
‘‘Tahap pemanasan persekitaran global semakin tidak menentu dan kesan disebabkan perubahan cuaca kian dirasai melangkaui seluruh dunia,” kata Ki- moon dalam satu kenyataan yang dikeluarkan baru-baru ini sebagai amaran bahawa manusia adalah pihak yang patut dipersalahkan terhadap pemanasan global dan perubahan iklim.
Tambah Ki-moon lagi, semua negara patut melihat kesan perubahan cuaca sebagai perkara merugikan mereka. Beliau menyifatkan dunia berada di ‘‘tahap kritikal’' dan jika tiada tindakan, keadaan akan bertambah lebih buruk.
‘‘Agak menyedihkan apabila di negara- negara miskin seperti Afrika dan negara- negara pulau kecil terpaksa menerima kesan teruk walaupun mereka bukan penyumbang utama kepada pemanasan global,” jelas beliau lagi.
Ki-moon menjadi harapan agensi alam sekitar PBB untuk memainkan peranan lebih penting bagi menjayakan Protokol Kyoto iaitu perjanjian dalam usaha mengurangkan kesan rumah hijau yang akan tamat pada 2012.
Sebagai pengguna, kita juga mempunyai pilihan sama ada mahu melihat masa depan bumi lebih sihat atau sebaliknya. Seperti ditegaskan Ki-moon, semua negara perlu bertindak. Rakyat Switzerland telah mengambil langkah dengan mengatakan kesediaan mereka mengurangkan kesan pemanasan global walau dengan apa cara sekalipun. Kita?

Al Gore, IPCC menang anugerah Nobel Keamanan

OSLO, Norway 12 Okt. – Jawatankuasa Nobel Norway hari ini mengumumkan Hadiah Nobel untuk keamanan dimenangi secara bersama oleh bekas Naib Presiden Amerika Syarikat, Al Gore dan Panel Antara Kerajaan untuk Perubahan Cuaca (IPCC).
Gore yang merupakan naib presiden di bawah pimpinan Bill Clinton dan calon presiden yang tewas kepada George W. Bush pada pilihan raya tahun 2000 telah membentuk semula imejnya sebagai pejuang perubahan iklim dunia melalui dokumentari An Inconvenient Truth yang memenangi anugerah Oscar pada 2006.
IPCC pula merupakan satu badan Pertubuhan Bangsa-Bangsa Bersatu (PBB) yang dianggotai 3,000 saintis atmosfera, pakar ais, ahli ekonomi, pakar ilmu lautan dan pakar pelbagai bidang lain bertanggungjawab memantau pemanasan global dan kesannya terhadap bumi.

intro on climate change and biodiversity

Climate Change and BiodiversityIntroduction

Climate change is the variation in either the mean state of the climate or in its variability, persisting for an extended period, typically decades or longer. It encompasses temperature increases ("global warming"), sea-level rises, changes in precipitation patterns, and increased frequencies of extreme weather events. In particular, recent findings by the scientific community suggest that global warming is causing shifts in species spatial distributions that average 6.1 km per decade towards the poles—or m per decade upward—in the direction predicted by climate change models, and that spring is on average, arriving 2.3 days earlier per decade in temperate latitudes. Entire regions are also suffering from the effects of global warming; in particular boreal and polar ecosystems.
Although past changes in the global climate resulted in major shifts in species ranges and marked reorganization of biological communities, landscapes, and biomes during the last 1.8 million years, these changes occurred in a landscape that was not as fragmented as it is today, and with little or no pressures from human activities. On the one hand, current climate change coupled with other human pressures is stressing biodiversity far beyond the levels imposed by the global climatic change that occurred in the recent evolutionary past. On the other hand, the human component needs to be incorporated when dealing with the impacts of climate change on biodiversity—that is, activities aimed at mitigating and adapting to climate change in which biodiversity considerations are essential.
The impacts of climate change on biodiversity are therefore of major concern to the Convention. At its fifth meeting in 2000, the Conference of the Parties highlighted the risks, in particular, to coral reefs (decision V/3) and to forest ecosystems (decision V/4), and drew attention to the serious impacts of loss of biodiversity of these systems on people’s livelihoods. More recently, the Conference of the Parties turned its attention to the potential impacts on biodiversity and ecosystems of the various options for mitigating or adapting to climate change and requested the Convention’s Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) to develop scientific advice on these issues (SBSTTA recommendation VI/7).
SBSTTA therefore established in 2001 an ad hoc technical expert group to carry out an assessment of the interlinkages between biodiversity and climate change and produced in 2003 a Technical Report based on the best available scientific knowledge, including that provided by the Intergovernmental Panel on Climate Change (IPCC). The reports concludes that there are significant opportunities for mitigating climate change, and for adapting to climate change while enhancing the conservation of biodiversity. The report also identifies a suite of tools, including the ecosystem approach, that can help decision makers assess the likely impacts and make informed choices, and examines the likely impacts of adaptation options in different terrestrial and aquatic ecosystems, covered by the thematic areas of the Convention.
At the 2002 World Summit on Sustainable Development (WSSD), world leader’s reaffirmed the central importance of the Convention on Biological Diversity and the United Nations Framework Convention on Climate Change (UNFCCC) as the objectives of the two conventions are mutually supportive: climate change is one of the threats to biodiversity, and the need for its rate to be reduced to allow ecosystems to adjust to climate change is recognized in the objective of the UNFCCC. In this context, and at its seventh meeting in 2004, the Conference of the Parties in its decision VII/15 further requested SBSTTA to develop advice for promoting synergy among activities to address climate change at the national, regional and international level, including activities to combat desertification and land degradation, and activities for the conservation of and sustainable use of biodiversity and invited the Conference of the Parties to the UNFCCC and to the United Nations Convention to Combat Desertification (UNCCD) to collaborate with the CBD to this end.

changing oceans:effect on biodiversity

Biodiversity and Climate Change 2000

Changing Oceans

Effects on biodiversity

PlanktonPhytoplankton are regarded as the most important biomass producers in the oceans. They are responsible for removing carbon dioxide from the atmosphere and transferring the carbon to other trophic levels. Phytoplankton also provide a vital link to deep ocean organisms when they die and organic material falls to the seabed. They are found in the top layer (the euphotic zone) where they receive enough solar radiation for their photosynthetic requirements as well as nutrients that are transported by the upwelling process.

Our knowledge of the impacts of temperature change on phytoplankton populations is poor and reliant on predictions of changing physical processes. Two such changes that could result from an increase in sea surface temperature are altered wind patterns and increased stratification of the water column. These effects could significantly reduce nutrients reaching the euphotic zone in certain parts of the world. This would lead to a decrease in primary production which would mean less overall productivity as well as less carbon dioxide removed from the atmosphere. The deep sea ecosystem would also be affected by a reduced carbon input.

Alterations in nutrient levels and temperature may also effect the species composition of phytoplankton populations in different regions, which would have serious repercussions for the rest of the marine environment. Not all types are readily eaten by zooplankton, some are even toxic, and different species also absorb carbon dioxide to varying degrees. A shift in species in any one area could lead to less carbon dioxide being absorbed from the atmosphere.

While phytoplankton are responsible for carbon fixation, bacterioplankton play a vital role in the mineralisation of nutrients and provide a trophic link to higher organisms. The breakdown products of organic matter are taken up by bacterioplankton and an indirect result of climate change could be a reduction in nutrients available to these microorganisms, impeding their function in the carbon flux of aquatic ecosystems.

The reduction in numbers or change in species composition of phytoplankton could lead to a reduction in zooplankton abundance. Since the 1950s scientists have recorded a decrease in zooplankton numbers in the Californian current. Whether this steady decline is attributable to a decrease in primary production or an increase in predation on the zooplankton, is not certain.

Plankton are not only affected by temperature changes but the increase in ultraviolet (UV) radiation, as a result of ozone depletion, also poses a threat to their survival. Studies have shown that UV radiation actually inhibits photosynthesis in phytoplankton but it is difficult to quantify these effects in the open ocean due to variation caused by factors such as vertical mixing and cloud cover. It is thought that rapid vertical mixing in the water column further inhibits photosynthesis whereas a greater cloud cover reduces the harmful effects of UV radiation. In addition UV rays affect growth and reproduction as well as the functioning of enzymes and cellular proteins in phytoplankton. Damage to phytoplankton has been demonstrated at the molecular, cellular, population and community levels but the effects of increased UV radiation at the ecosystem level remain uncertain.

Bacterioplankton seem to lack UV-screening pigments and radiation affects the enzymes responsible for breaking down their food. When bacterioplankton move to deeper waters, however, the photorepair process carried out by UV-A (blue light) allows the take up of organic breakdown products. More research is required to determine the true impact of UV radiation on these minute but important organisms.

It has also been demonstrated that zooplankton are damaged by UV radiation and even small increases in UV exposure could result in significant reductions in the consumer community.

Fish

A decrease in plankton production, which could result from a changing climate, would mean less food for fish populations. In addition, temperature increases are expected to shift many species polewards where the climate is cooler and hence metabolic rates could be kept low. Warm-water species may increase in abundance with more favourable conditions at lower latitudes. This situation could have a significant impact on commercial fisheries such as that of Atlantic cod as this species feeds on temperature-sensitive ones like mackerel and herring. Research into the decline of important salmon stocks on the west coast of Canada and Alaska has suggested that these temperature changes are already having an impact.

Natural climate variability experienced during the El Niño Southern Oscillation (ENSO) event provides further warning of the potential impacts of climate change. In the past ENSO events have led to a mass die-off of fish species such as Peruvian anchovies and sardines. Further large-scale mortalities could result if the unusual temperatures experienced during an ENSO period become more commonplace with climate change.

The eggs and larvae of many fish species are sensitive to ultraviolet (UV) radiation. The naturally high mortality of fish larvae make it difficult to accurately assess the direct effects of ozone depletion when the primary causes of population decline are predation, poor food supply for larvae, overfishing of adults, water temperature, pollution and disease. Nonetheless, UV radiation appears to be harmful at both primary and secondary production levels. The number of variables involved make predictions of impacts on a global scale and further along the food web a complex task.

Seabirds

Many of the seabirds that prey on fish and plankton are likely to have their food supply reduced or relocated if the predicted effects of climate change on lower trophic levels occur. The natural climate variability of El Niño Southern Oscillation (ENSO) events has already given us an insight into what we may expect with more permanent climate change. Starvation was unmistakeably the cause of a large decline in Alaskan shearwaters and common murres during the 1997-98 El Niño Southern Oscillation and cormorants and pelicans experienced mass mortalities during the 1982-1983 event. This is not, however, a simple cause and effect relationship as other species, such as Leach's storm petrel in the Californian current, have increased in number during warmer periods and may benefit from such changes in climate. Some species have shown an ability to shift their food sources when preferred prey are unavailable.

A lack of food also affects the reproductive success of seabirds with a reduction in numbers of eggs produced, those successfully hatching and the number of breeding pairs. Shifts in food supplies associated with ENSO events have been blamed for reproductive failure in some seabirds. Population changes experienced by species off California, where the frequency of warm sea surface temperatures has been increasing since 1977, have been well-documented. There is also evidence that some species of seabirds are changing their breeding season during the periods of warmer sea temperatures. Cassin's auklets, off the coast of British Columbia in Canada, normally time their breeding cycle so their chicks hatch right after the zooplankton bloom but now the chicks hatch a month before the peak of zooplankton production to avoid the warmer temperatures. The survival rate of both adults and chicks is affected by these changes.

The predicted increase in storm frequency and severity with climate change may directly affect some seabird populations. Studies on common guillemots in the north Atlantic show that storms appear to impede fishing activities, reducing the size and number of fish that adults can feed to their chicks.

The mobile nature of seabirds means that they will be more able to shift their distribution away from the warmer areas towards the poles. Adelie penguins, however, are resident in the Antarctic and have nowhere cooler to migrate to. Indeed a decrease in the availability of sea ice, where this species overwinters, has led to its decline in numbers. Conversely, South Polar skuas and blue-eyed shags prefer open water and have been increasing in numbers and extending their geographic ranges further south.


Marine mammals

The predicted reduction in primary productivity that could result from increased sea temperatures would inevitably reach the top of the food web with supplies for marine mammals being affected. Natural climate variability during an El Niño Southern Oscillation (ENSO) event has reduced the abundance of important prey species in certain regions of the world and the impacts on marine mammals have been studied.


Young female seals and sea lions and the young themselves were most severely affected in the eastern Pacific area during the 1982-83 ENSO. These females were required to travel away from their young in search of food and with reductions in prey they had to travel further and expend more energy to achieve this. This situation has resulted in a decline in the physical condition of females as well as reduced milk production and pregnancy rates. Young seals and sea lions suffered with higher than usual death rates and reduced growth rates as their mothers were less able to produce milk and left them alone for longer periods. In addition it took several years for the fish stocks and hence the pinniped populations to recover. Other species, such as the Antarctic crabeater seal, are declining in numbers due to their dependence on the decreasing areas of sea ice at high latitudes.

Animals that prefer a more open water situation, like the Southern elephant and Southern fur seals, appear to be increasing in numbers. Shifts in species composition such as these could become more common place as environmental conditions change to favour one lifestyle above another.

Sea ice supports other marine mammals like walruses and ringed seals by providing critical breeding and resting-places. Polar bears spend considerable periods on the ice while catching their preferred prey, seals. Temperature increases in the Arctic have caused sea ice to break up earlier in the summer allowing polar bears less time to build up vital fat reserves to last them through the winter months. If this trend continues a decline in the weight of adult polar bears and birthrates, already documented in Hudson Bay populations, will become a serious threat to their survival.

The impacts of climate change on whales and dolphins could be considerable but difficult to quantify at this trophic level and currently little evidence exists to show how they have been affected. The availability of food may pose a problem for some species of cetaceans especially those visiting important feeding grounds in polar regions. The increase in temperature already experienced in these areas has led to a reduction in the thickness and extent of sea ice and could decrease the abundance of phytoplankton. In the Southern Ocean krill (Euphausea superba), are an important invertebrate eaten by many species of whales and they rely on sea ice for food and protection. In the Arctic key prey species of cetaceans, such as copepods and plankton-feeding fish, could also be reduced. Some cetacean species may be able to adapt to another food source but others, such as belugas and narwhals, may be more dependent on the plankton-feeding prey.


An increase in temperature could have some secondary effects on cetaceans. Melting sea ice would open up the North West Passage into the Arctic and expose cetaceans to increased ship traffic and mineral exploitation. Collisions with ships, disruption of migration patterns, increased mortality through stress and interference with communications would be just a few of the inevitable results.

Changing Oceans introduction
Physical and chemical effects of climate change
Physical effects of ozone depletion and enhanced ultraviolet radiation
Effects on important ecosystems



Warnings from the
Wild Documentary

Golongan Media Sukar Memahami Isu Pemanasan Global

KUALA LUMPUR, 30 Mei (Bernama) -- Kebanyakan wartawan media sukar memahami isu-isu mengenai pemanasan global dan perubahan cuaca yang semakin mendapat perhatian dunia pada masa ini, kata Pengarah Presiden Radio Republik Indonesia (RRI) Parni Hadi.

Katanya masalah itu adalah disebabkan laporan penemuan saintifik terhadap isu-isu itu bercorak begitu akademik dengan jadual, grafik dan penjelasan yang mengelirukan.

"Jika wartawan sendiri tidak dapat memahaminya, bagaimana dengan orang awam...oleh itu terdapat keperluan mendesak untuk latihan kewartawanan dalam isu-isu alam persekitaran khususnya pemanasan global dan perubahan cuaca," katanya.

Beliau berkata demikian ketika menyampaikan kertas kerja bertajuk "Peranan Media Dalam Menangani Perubahan Cuaca" pada Sidang Kemuncak Media Asia 2007 di sini hari ini.

Parni juga berkata latihan juga diperlukan untuk saintis menyediakan penemuan saintifik secara mudah difahami oleh orang awam di mana ia berbeza dengan penulisan untuk jurnal akademik.

Indonesia dijadual menjadi tuan rumah Konvensyen Perubahan Cuaca Pertubuhan Bangsa-bangsa Bersatu (UNCFCC) di Bali dari 3 hingga 14 Dis ini dengan penyertaan 10,000 perwakilan dari 189 negara termasuk 2,500 wartawan.

Parni berkata ke arah penganjuran konvensyen tersebut, kerajaan Indonesia telah meminta golongan media di negara itu meningkatkan kempen kesedaran di kalangan orang awam mengenai kesan bahaya perubahan cuaca ke atas ekonomi dan kesihatan penduduk.

Sementara itu, seorang lagi penceramah, Georges Leclere, Penasihat Media Global, dari LGMA Inc., Amerika Syarikat, mencadangkan sebuah program realiti mengenai penentangan terhadap pemanasan global disiarkan pada waktu perdana.

Berjudul "Go for the Green", merupakan program realiti berpasukan dengan tujuan mengurangkan kesan pemanasan global di samping hiburan, memberi ganjaran dan membuka minda penonton.

"Jika Asia dapat menerima cadangan program televisyen ini, maka ia boleh menerajui usaha menentang pemanasan global di peringkat tempatan dan serantau," katanya.

-- BERNAMA

Sea Level Changes

Sea levels are rising worldwide and along much of the U.S. coast. (IPCC, 2007) Tide gauge measurements and satellite altimetry suggest that sea level has risen worldwide approximately 4.8-8.8 inches (12-22 cm) during the last century (IPCC, 2007). A significant amount of sea level rise has likely resulted from the observed warming of the atmosphere and the oceans.

According to the Intergovernmental Panel on Climate Change (IPCC), the primary factors driving current sea level rise include:

• the expansion of ocean water caused by warmer ocean temperatures
• melting of mountain glaciers and small ice caps
• (to a lesser extent) melting of the Greenland Ice Sheet and the Antarctic Ice Sheet

Other factors may also be responsible for part of the historic rise in sea level, including the pumping of ground water for human use, impoundment in reservoirs, wetland drainage, deforestation, and the melting of polar ice sheets in response to the warming that has occurred since the last ice age.

Considering all of these factors, scientists still cannot account for the last century's sea level rise in its entirety. It is possible that some contributors to sea level rise have not been documented or well-quantified.

The rate of sea level rise increased during the 1993-2003 period compared with the longer-term average (1961-2003), although it is unclear whether the faster rate reflects a short-term variation or an increase in the long-term trend. (IPCC, 2007)

While the global average sea level rise of the 20th century was 4.4-8.8 inches, the sea level has not risen uniformly from region to region.

Figure 1: U.S. Sea Level Trends Source: Monthly and Annual Mean Sea Level Station Files from the Permanent Service for Mean Sea Level (PSMSL) at the Proudman Oceanographic Laboratory

In the United States:

• Sea level has been rising 0.08-0.12 inches per year (2.0-3.0 mm per year) along most of the U.S. Atlantic and Gulf coasts.
• The rate of sea level rise varies from about 0.36 inches per year (10 mm per year) along the Louisiana Coast (due to land sinking), to a drop of a few inches per decade in parts of Alaska (because land is rising). See Figure 1 for sea level trends in selected cities.

Globally (IPCC, 2007):

• Indonesia, Thailand, and Bangladesh are experiencing above-average sea level rise.
• Northwestern Australia is experiencing below-average sea level rise, a trend that is evident in much of the ocean between western Australia and East Africa.
• Most of the Pacific and Atlantic basins are experiencing average to above-average sea level rise.
• Many coastal areas outside of the U.S., Europe and Japan have too few tide gauges to be sure about long-term trends in regional sea level rise.

Is the rate of sea level rise accelerating?

• The IPCC expresses high confidence that the rate of observed sea level rise increased from the mid 19th to the mid 20th century. During the 20th century, sea level rose at an average rate of 4.8 to 8.8 inches per century (1.2-2.2 mm/year). (IPCC, 2007)
• Tide gauges show little or no acceleration during the 20th century.
• Satellite measurements estimate that sea level has been rising at a rate of 9 to 15 inches per century (2.4-3.8 mm/yr) since 1993, more than 50% faster than the rate that tide gauges estimate over the last century. (IPCC, 2007)

The Future Climate Change Sea Level Rise page contains projections for future sea level rise.

Precipitation and Storm Changes

Precipitation Changes

Increasing temperatures tend to increase evaporation which leads to more precipitation (IPCC, 2007). As average global temperatures have risen, average global precipitation has also increased. According to the IPCC, the following precipitation trends have been observed:

• Precipitation has generally increased over land north of 30°N from 1900-2005, but has mostly declined over the tropics since the 1970s. Globally there has been no statistically significant overall trend in precipitation over the past century, although trends have widely by region and over time.
• It has become significantly wetter in eastern parts of North and South America, northern Europe, and northern and central Asia, but drier in the Sahel, the Mediterranean, southern Africa and parts of southern Asia.
• Changes in precipitation and evaporation over the oceans are suggested by freshening of mid- and high-latitude waters (implying more precipitation), along with increased salinity in low-latitude waters (implying less precipitation and/or more evaporation).
• There has been an increase in the number of heavy precipitation events over many areas during the past century, as well as an increase since the 1970s in the prevalence of droughts—especially in the tropics and subtropics.

United States Precipitation Changes

Observations compiled by NOAA's National Climatic Data Center show that over the contiguous U.S., total annual precipitation increased at an average rate of 6.1 percent per century since 1900, although there was considerable regional variability. The greatest increases came in the East North Central climate region (11.6 percent per century) and the South (11.1 percent). Hawaii was the only region to show a decrease (-9.25 percent).

Figure 1: Annual Precipitation Trends 1901-2005. Click on Thumbnail for full size image. Data courtesy NOAA's National Climatic Data Center.

In the Northern Hemisphere's mid- and high latitudes, the precipitation trends are consistent with climate model simulations that predict an increase in precipitation due to human-induced warming. By contrast, the degree to which human influences have been responsible for any variations in tropical precipitation patterns is not well understood or agreed upon, as climate models often differ in their regional projections (IPCC, 2007).

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Storm Changes

There is large natural variability in the intensity and frequency of mid latitude storms and associated features such as thunderstorms, hail events and tornadoes. To date, there is no long-term evidence of systematic changes in these types of events over the course of the past 100 years (IPCC, 2007). Analyses of severe storms are complicated by factors including the localized nature of the events, inconsistency in data observation methods, and the limited areas in which studies have been performed.

The frequency and intensity of tropical storm systems have also varied over the 20th century on annual, decadal and multi-decadal time scales. For example, in the Atlantic basin, the period from about 1995-2005 was extremely active both in terms of the overall number of tropical storm systems including hurricanes as well as in storm intensity. However, the two to three decades prior to the mid-1990s were characterized as a relatively inactive period.

Following the Atlantic hurricane season of 2005, which set a record with 27 named storms, a great deal of attention has focused on the relationship between hurricanes and climate change. Numerous studies were published on possible linkages, with a range of conclusions. To provide an updated assessment of the current state of knowledge of the impact of global warming on tropical systems, the World Meteorological Organization’s hurricane researchers published a consensus statement. Their conclusions include (WMO, 2006):

“Though there is evidence both for and against the existence of a detectable anthropogenic signal in the tropical cyclone climate record to date, no firm conclusion can be made on this point.”

There is general agreement that no individual events in [2004 and 2005] can be attributed directly to the recent warming of the global oceans…[but] it is possible that global warming may have affected the 2004-2005 group of events as a whole.”