Purchasing green energy through the electrical grid

In several countries with common carrier arrangements, electricity retailing arrangements make it possible for consumers to purchase green electricity (renewable electricity) from either their utility or a green power provider.

When energy is purchased from the electricity network, the power reaching the consumer will not necessarily be generated from green energy sources. The local utility company, electric company, or state power pool buys their electricity from electricity producers who may be generating from fossil fuel, nuclear or renewable energy sources. In many countries green energy currently provides a very small amount of electricity, generally contributing less than 2 to 5% to the overall pool. In some U.S. states, local governments have formed regional power purchasing pools using Community Choice Aggregation and Solar Bonds to achieve a 51% renewable mix or higher, such as in the City of San Francisco.

By participating in a green energy program a consumer may be having an effect on the energy sources used and ultimately might be helping to promote and expand the use of green energy. They are also making a statement to policy makers that they are willing to pay a price premium to support renewable energy. Green energy consumers either obligate the utility companies to increase the amount of green energy that they purchase from the pool (so decreasing the amount of non-green energy they purchase), or directly fund the green energy through a green power provider. If insufficient green energy sources are available, the utility must develop new ones or contract with a third party energy supplier to provide green energy, causing more to be built. However, there is no way the consumer can check whether or not the electricity bought is "green" or otherwise.

In some countries such as the Netherlands, electricity companies guarantee to buy an equal amount of 'green power' as is being used by their green power customers. The Dutch government exempts green power from pollution taxes, which means green power is hardly any more expensive than other power.

In the United States, one of the main problems with purchasing green energy through the electrical grid is the current centralized infrastructure that supplies the consumer’s electricity. This infrastructure has lead to increasingly frequent brown outs and black outs, high CO2 emissions, higher energy costs, and power quality issues . An additional $450 billion will be invested to expand this fledgling system over the next 20 years in order to meet increasing demand . In addition, this centralized system is now being further overtaxed with the incorporation of renewable energies such as wind, solar, and geothermal energies. Renewable resources, due to the amount of space they require, are often located in remote areas where there is a lower energy demand. The current infrastructure would make transporting this energy to high demand areas, such as urban centers, highly inefficient and in some cases impossible. In addition, despite the amount of renewable energy produced or the economic viability of such technologies only about 20 percent will be able to be incorporated into the grid. In order to have a more sustainable energy profile, the United States has to move towards implementing changes to the electrical grid that will accommodate a mixed-fuel economy.

However, several initiatives are being proposed to mitigate these distribution problems. First and foremost, the most effective way to reduce our nation’s CO2 emissions and slow global warming is through conservation efforts. Opponents of our current electrical grid have also advocated for decentralizing the grid. This system would increase efficiency by reducing the amount of energy lost in transmission. It would also be economically viable as it would reduce the amount of power lines that will need to be constructed in the future to keep up with demand. Merging heat and power in this system would create added benefits and help to increase its efficiency by up to 80-90%. This is a significant increase from the current fossil fuel plants which only have an efficiency of 34% .

A more recent concept for improving our electrical grid is to beam microwaves from Earth-orbiting satellites or the moon to directly when and where there is demand. The power would be generated from solar energy captured on the lunar surface In this system, the receivers would be “broad, translucent tent-like structures that would receive microwaves and convert them to electricity”. NASA said in 2000 that the technology was worth pursuing but it is still too soon to say if the technology will be cost-effective.

Abuses

In countries where suppliers are legally obliged to purchase a proportion of their electricity from renewable sources (for example under the Renewables Obligation in the United Kingdom), there is a danger that energy suppliers may sell such green electricity under a premium "green energy" tariff, rather than sourcing additional green electricity supplies. Where a Renewable Energy Certificate or similar scheme is in operation it is also possible for the energy supplier to sell the green electricity to the consumer, and also sell the certificate to another supplier who has failed to meet their quota, rather than "retiring" the certificate from the marketplace. In other cases green energy tariffs may involve carbon offsetting rather than purchasing or investing in renewable energy.

Certification schemes to minimise these and similar questionable practices are in place or are being developed in a few countries.

International standards

The World Wide Fund for Nature and several green electricity labelling organizations have created the Eugene Green Energy Standard under which the national green electricity certification schemes can be accredited to ensure that the purchase of green energy leads to the provision of additional new green energy resources.

From Wikipedia, the free encyclopedia

Panel surya

Panel surya adalah alat yang terdiri dari sel surya yang mengubah cahaya menjadi listrik. Mereka disebut surya atas matahari atau "sol" karena matahari merupakan sumber cahaya terkuat yang dapat dimanfaatkan. Panel surya sering kali disebut sel photovoltaic, photovoltaic dapat diartikan sebagai "cahaya-listrik". Sel surya atau sel PV bergantung pada efek photovoltaic untuk menyerap energi matahari dan menyebabkan arus mengalir antara dua lapisan bermuatan yang berlawanan.

Jumlah penggunaan panel surya di porsi pemroduksian listrik dunia sangat kecil, tertahan oleh biaya tinggi per wattnya dibandingkan dengan bahan bakar fosil - dapat lebih tinggi sepuluh kali lipat, tergantung keadaan. Mereka telah menjadi rutin dalam beberapa aplikasi yang terbatas seperti, menjalankan "buoy" atau alat di gurun dan area terpencil lainnya, dan dalam eksperimen lainnya mereka telah digunakan untuk memberikan tenaga untuk mobil balap dalam kontes seperti Tantangan surya dunia di Australia.

Sekarang ini biaya panel listrik surya membuatnya tidak praktis untuk penggunaan sehari-hari di mana tenaga listrik "kabel" telah tersedia. Bila biaya energi naik dalam jangka tertentu, atau bila penerobosan produksi terjadi yang mengurangi ongkos produksi panel surya, ini sepertinya tidak akan terjadi dalam waktu dekat.

Pada 2001 Jepang telah memasang kapasitas 0,6 MWp tenaga surya puncak, sementara itu Jerman memilik 0,26 MWp dan Amerika Serikat 0,16 MWp. Pada saat ini tenaga listrik surya seluruh dunia kira-kira sama dengan yang diproduksi oleh satu kincir angin bear. Di AS biaya pemasangan panel surya ini telah jatuh dari $55 per watt puncak pada 1976 menjadi $4 per watt peak di 2001.

Dari Wikipedia bahasa Indonesia, ensiklopedia bebas

Energi bio dari limbah

Penggunaan limbah biomassa untuk memproduksi energi mampu mengurangi berbagai permasalahan manajemen polusi dan pembuangan, mengurangi penggunaan bahan bakar fosil, serta mengurangi emisi gas rumah kaca. Uni Eropa telah mempublikasikan sebuah laporan yang menyoroti potensi energi bio yang berasal dari limbah untuk memberikan kontribusi bagi pengurangan pemanasan global. Laporan itu menyimpulkan bahwa di tahun 2020 nanti 19 juta ton minyak tersedia dari biomassa, 46% dari limbah bio: limbah padat perkotaan, residu pertanian, limbah peternakan, dan aliran limbah terbiodegradasi yang lain.

Tempat penampungan akhir sampah menghasilkan sejumlah gas karena limbah yang dipendam di dalamnya mengalami pencernaan anaerobik. Secara kolektif gas-gas ini dikenal sebagai landfill gas (LFG) atau gas tempat pembuangan akhir sampah. Landfill gas bisa dibakar baik secara langsung untuk menghasilkan panas atau menghasilkan listrik bagi konsumsi publik. Landfill gas mengandung sekitar 50% metana, gas yang juga terdapat di dalam gas alam.

Biomassa bisa berasal dari limbah materi tanaman. Gas dari tempat penampungan kotoran manusia dan hewan yang memasuki atmosfir merupakan hal yang tidak diinginkan karena metana adalah salah satu gas rumah kaca yang potensil pemanasan globalnya melebihi karbondioksida. Frank Keppler dan Thomas Rockmann menemukan bahwa tanaman hidup juga memproduksi metana CH4.

Dari Wikipedia bahasa Indonesia, ensiklopedia bebas

Biofuel

Biofuel adalah setiap bahan bakar baik padatan, cairan ataupun gas yang dihasilkan dari bahan-bahan organik. Biofuel dapat dihasilkan secara langsung dari tanaman atau secara tidak langsung dari limbah industri, komersial, domestik atau pertanian. Ada tiga cara untuk pembuatan biofuel: pembakaran limbah organik kering (seperti buangan rumah tangga, limbah industri dan pertanian); fermentasi limbah basah (seperti kotoran hewan) tanpa oksigen untuk menghasilkan biogas (mengandung hingga 60 persen metana), atau fermentasi tebu atau jagung untuk menghasilkan alkohol dan ester; dan energi dari hutan (menghasilkan kayu dari tanaman yang cepat tumbuh sebagai bahan bakar).

Proses fermentasi menghasilkan dua tipe biofuel: alkohol dan ester. Bahan-bahan ini secara teori dapat digunakan untuk menggantikan bahan bakar fosil tetapi karena terkadang diperlukan perubahan besar pada mesin, biofuel biasanya dicampur dengan bahan bakar fosil. Uni Eropa merencanakan 5,75 persen etanol yang dihasilkan dari gandum, bit, kentang atau jagung ditambahkan pada bahan bakar fosil pada tahun 2010 dan 20 persen pada 2020. Sekitar seperempat bahan bakar transportasi di Brazil tahun 2002 adalah etanol.

Biofuel menawarkan kemungkinan memproduksi energi tanpa meningkatkan kadar karbon di atmosfir karena berbagai tanaman yang digunakan untuk memproduksi biofuel mengurangi kadar karbondioksida di atmosfir, tidak seperti bahan bakar fosil yang mengembalikan karbon yang tersimpan di bawah permukaan tanah selama jutaan tahun ke udara. Dengan begitu biofuel lebih bersifat carbon neutral dan sedikit meningkatkan konsentrasi gas-gas rumah kaca di atmosfir (meski timbul keraguan apakah keuntungan ini bisa dicapai di dalam prakteknya). Penggunaan biofuel mengurangi pula ketergantungan pada minyak bumi serta meningkatkan keamanan energi.

Ada dua strategi umum untuk memproduksi biofuel. Strategi pertama adalah menanam tanaman yang mengandung gula (tebu, bit gula, dan sorgum manis) atau tanaman yang mengandung pati/polisakarida (jagung), lalu menggunakan fermentasi ragi untuk memproduksi etil alkohol. Strategi kedua adalah menanam berbagai tanaman yang kadar minyak sayur/nabatinya tinggi seperti kelapa sawit, kedelai, alga, atau jathropa. Saat dipanaskan, maka keviskositasan minyak nabati akan berkurang dan bisa langsung dibakar di dalam mesin diesel, atau minyak nabati bisa diproses secara kimia untuk menghasilkan bahan bakar seperti biodiesel. Kayu dan produk-produk sampingannya bisa dikonversi menjadi biofuel seperti gas kayu, metanol atau bahan bakar etanol.

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Kegunaan ozon

Ozon digunakan dalam bidang pengobatan untuk mengobati pasien dengan cara terawasi dan mempunyai penggunaan yang meluas seperti di Jerman. Di antaranya ialah untuk perawatan kulit terbakar.

Sedangkan dalam perindustrian, ozon digunakan untuk:

• mengenyahkan kuman sebelum dibotolkan (antiseptik),
• menghapuskan pencemaran dalam air (besi, arsen, hidrogen sulfida, nitrit, dan bahan organik kompleks yang dikenal sebagai warna),
• membantu proses flokulasi (proses pengabungan molekul untuk membantu penapis menghilangkan besi dan arsenik),
• mencuci, dan memutihkan kain (dipaten),
• membantu mewarnakan plastik,
• menentukan ketahanan getah.
  

Dari Wikipedia bahasa Indonesia, ensiklopedia bebas

Ancaman dari klorofluorokarbon (CFC)

Ancaman yang diketahui terhadap keseimbangan ozon adalah kloroflorokarbon (CFC) buatan manusia yang meningkatkan kadar penipisan ozon menyebabkan kemerosotan berangsur-angsur dalam tingkat ozon global.

CFC digunakan oleh masyarakat modern dengan cara yang tidak terkira banyaknya, dalam kulkas, bahan dorong dalam penyembur, pembuatan busa dan bahan pelarut terutama bagi kilang-kilang elektronik.

Masa hidup CFC berarti 1 molekul yang dibebaskan hari ini bisa ada 50 hingga 100 tahun dalam atmosfer sebelum dihapuskan.

Dalam waktu kira-kira 5 tahun, CFC bergerak naik dengan perlahan ke dalam stratosfer (10 – 50 km). Di atas lapisan ozon utama, pertengahan julat ketinggian 20 – 25 km, kurang sinar UV diserap oleh ozon. Molekul CFC terurai setelah bercampur dengan UV, dan membebaskan atom klorin. Atom klorin ini juga berupaya untuk memusnahkan ozon dan menghasilkan lubang ozon.

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Prof. Dr. Ir. Purwanto, DEA.: Teknologi Bersih Cegah Pencemaran

Written by Istadi
Wednesday, 21 January 2009
Sumber http://www.undip.ac.id/



Sektor industri salah satu penyumbang devisa. Namun sektor itu juga menghasilkan limbah dan emisi. ”Jika tak ditangani dengan baik akan menimbulkan efek negatif bagi lingkungan,” ujar Prof Dr Ir Purwanto DEA. Guru besar ke-159 Undip dari Jurusan Teknik Kimia Fakultas Teknik itu mengemukakan hal tersebut saat jumpa pers di rektorat Undip, kampus Pleburan, kemarin. Peraih gelar doktor teknologi proses kimia dari ENSIGC-INP Toulouse, Prancis, itu memperkirakan 645.120 industri di Jawa Tengah (2007) punya potensi limbah bahan berbahaya dan beracun 783.367,5 ton/tahun. Guru besar yang akan dikukuhkan 22 Januari itu menyayangkan persoalan lingkungan acap ditanggapi secara pasif dengan membiarkan limbah. Atau, secara reaktif dengan mengolah limbah untuk memenuhi baku mutu dan menaati peraturan.

”Padahal, produksi bersih memadukan aspek ekonomi dan lingkungan dengan meningkatkan efisiensi dan mencegah pencemaran. Itulah yang menjadi dasar pembangunan sektor industri berkelanjutan,” katanya.

Lima R

Pria kelahiran Demak, 28 Desember 1961, itu menuturkan produksi bersih menggunakan strategi 5R, yakni rethink (berpikir ulang), reduce (pengurangan), reuse (pakai ulang), recycle (daur ulang), dan recovery (ambil ulang). ”Namun upaya mencegah dan mengurangi limbah dari sumbernya belum maksimal. Padahal, saat krisis global seperti saat ini, penerapan 5R akan meningkatkan efisiensi sumber daya bahan, energi, dan air.”

Produksi bersih dapat meningkatkan efisiensi. Dan, itu meliputi tata kelola industri yang baik, penggantian bahan baku ramah lingkungan, perbaikan proses dan teknologi, pemakaian teknologi bersih, dan modifikasi produk yang lebih ramah lingkungan.

Industri skala kecil menengah, ujar dia, lebih mudah menjalankan tata kelola dan perbaikan proses dan teknologi. ”Industri besar dapat mengganti teknologi dengan lebih bersih dan merancang produk yang tak berdampak negatif terhadap lingkungan.”

Ketua Program Magister Ilmu Lingkungan Undip itu menegaskan industri bersih skala makro di kawasan industri harus jadi prioritas pembangunan industri berkelanjutan melalui jejaring dan simbiosis industri. ”Kawasan yang hanya menyediakan lahan industri sudah saatnya memikirkan pemakaian sumber daya dan pelestarian lingkungan demi generasi mendatang

Perunggasan nasional dalam kurun waktu hampir satu dekade telah mengalami banyak perubahan. Perubahan itu antara lain sistem pemeliharaan, dari kandang terbuka menjadi kandang tertutup. Status dan jumlah kepemilikan ternak peliharaan, dari peternak kecil berkembang menjadi peternak menengah hingga besar. Meski demikian, masalah pakan belum banyak berubah karena masih bergantung pada pakan produksi pabrikan.

”Akibatnya, pada saat krisis ekonomi (1997-1998), subsektor peternakan, khususnya unggas, utamanya ayam ras petelur dan pedaging mengalami penurunan populasi karena harga pakan meningkat tajam dan tidak diikuti kenaikan harga daging dan telur,” ungkap Prof Dr Ir Bambang Sukamto SU. Dosen Jurusan Nutrisi dan Makanan Ternak Fakultas Peternakan Undip itu akan dikukuhkan sebagai guru besar ke-160 Undip, 22 Januari 2009 besok.

Beberapa tahun kemudian, lanjut dia, perunggasan nasional mulai bangkit kembali. Namun pada 2004-2006 kembali terpuruk akibat penyakit flu burung (Avian Influenza/AI) yang menyebar hampir di seluruh kawasan. Tidak saja di Indonesia tetapi juga di negara-negera Asia dan Eropa. ''Kondisi ini berakibat pada ketersediaan protein hewani yang belum mencukupi kebutuhan nasional.”

Sebagai alternatif untuk memenuhi kebutuhan daging ayam, dilakukan suplai ayam lokal. Ditinjau dari ketahanan terhadap penyakit, ungkap dia, ayam lokal memiliki kekebalan maternal dan respons kekebalan primer yang lebih tinggi dibandingkan ayam ras. ”Ini merupakan alternatif sebagai penyangga ketahanan pangan asal ternak.”

Sistem Tradisional

Bambang yang meraih gelar doktor ilmu ternak dari Unpad Bandung itu mengakui, prestasi produksi ayam lokal yang dipelihara oleh masyarakat masih relatif rendah. Hal ini disebabkan oleh sistem pemeliharaan yang masih bersifat semi intensif, bahkan tradisional.

Pakan yang diberikan, ungkapnya, masih belum memenuhi persyaratan gizi. Terlebih dengan pola pemeliharaan umbaran yang sangat tergantung pada ketersediaan pakan di lingkungan setempat yang notabene tidak menentu kualitasnya dan tidak menunjang peningkatan produksi.

Ayam lokal, sambung pria kelahiran Tuban, 16 Februari 1953, itu mempunyai nilai ekonomi yang lebih baik apabila sistem pemeliharaan dan kualitas pakan yang diberikan dapat memenuhi kebutuhannya.

”Oleh karena itu, diperlukan perbaikan pakan yang disusun berdasarkan kebutuhan energi dan protein serta zat-zat pakan lainnya yang berkeseimbangan.”Ketersediaan pangan yang berasal dari dalam negeri seperti keberadaan ayam lokal di tengah masyarakat, tutur Bambang, merupakan kunci sukses sistem ketahanan pangan. Oleh karena itu, diperlukan kebijakan yang kondusif untuk mendukung peningkatan produksi pangan dalam negeri. Bantuan teknis produksi, akses permodalan yang mudah dengan bunga lunak bagi para peternak kecil merupakan insentif produksi yang sangat diharapkan.

Suami Siti Rahayuni itu menguraikan, ayam lokal yang dipelihara secara intensif dengan pemberian pakan yang sesuai standar kebutuhan, meningkatkan performa produksi. ''Dan yang penting diketahui, ayam lokal di Jateng, mampu memberikan kontribusi penyediaan telur dan daging dalam rangka membantu ketahanan pangan.''

Projections of future climate change

Coupled ocean-atmosphere GCMs use transient climate simulations to project/predict future temperature changes under various scenarios. These can be idealised scenarios (most commonly, CO2 increasing at 1%/yr) or more realistic (usually the "IS92a" or more recently the SRES scenarios). Which scenarios should be considered most realistic is currently uncertain, as the projections of future CO2 (and sulphate) emission are themselves uncertain.

The 2001 IPCC Third Assessment Report figure 9.3 shows the global mean response of 19 different coupled models to an idealised experiment in which CO2 is increased at 1% per year [14]. Figure 9.5 shows the response of a smaller number of models to more realistic forcing. For the 7 climate models shown there, the temperature change to 2100 varies from 2 to 4.5 °C with a median of about 3 °C.

Future scenarios do not include unknowable events - for example, volcanic eruptions or changes in solar forcing. These effects are believed to be small in comparison to GHG forcing in the long term, but large volcanic eruptions, for example, are known to exert a temporary cooling effect.

Human emissions of GHGs are an external input to the models, although it would be possible to couple in an economic model to provide these as well. Atmospheric GHG levels are usually supplied as an input, though it is possible to include a carbon cycle model including land vegetation and oceanic processes to calculate GHG levels.

From Wikipedia, the free encyclopedia

The demise of the Greenland Norse settlements

From Wikipedia, the free encyclopedia



There are many theories as to why the Norse settlements collapsed in Greenland. Jared Diamond, author of Collapse: How Societies Choose to Fail or Succeed, suggests that some or all of five factors contributed to the demise of the Greenland colony: cumulative environmental damage, gradual climate change, conflicts with hostile neighbors, the loss of contact and support from Europe, and, perhaps most crucial, cultural conservatism and failure to adapt to an increasingly harsh natural environment. Numerous studies have tested these hypotheses and some have led to significant discoveries. On the other hand there are dissenters: In The Frozen Echo, Kirsten Seaver contests some of the more generally-accepted theories about the demise of the Greenland colony. Thus Seaver asserts that the Greenland colony, towards the end, was healthier than Diamond and others have thought. Seaver believes that the Greenlanders cannot have starved to death. They may rather have been wiped out by Inuit or unrecorded European attacks, or they may have abandoned the colony to return to Iceland or to seek out new homes in Vinland. However, these arguments seem to conflict with the physical evidence from archeological studies of the ancient farm sites. The paucity of personal belongings at these sites is typical of North Atlantic Norse sites that were abandoned in an orderly fashion, with any useful items being deliberately removed but to others it suggests a gradual but devastating impoverishment. Midden heaps at these sites do show an increasingly impoverished diet for humans and livestock.

Greenland was always colder in winter than Iceland and Norway, and its terrain less hospitable to agriculture. Erosion of the soil was a danger from the beginning, one that the Greenland settlements may not have recognized until it was too late. For an extended time, nonetheless, the relatively warm West Greenland current flowing northwards along the southwestern coast of Greenland made it feasible for the Norse to farm much as their relatives did in Iceland or northern Norway. Palynologists' tests on pollen counts and fossilized plants prove that the Greenlanders must have struggled with soil erosion and deforestation. As the unsuitability of the land for agriculture became more and more patent, the Greenlanders resorted first to pastoralism and then to hunting for their food. But they never learned to use the hunting techniques of the Inuit, one being a farming culture, the other living on hunting in more northern areas with pack ice.

To investigate the possibility of climatic cooling, scientists drilled into the Greenland ice caps to obtain core samples. The oxygen isotopes from the ice caps suggested that the Medieval Warm Period had caused a relatively milder climate in Greenland, lasting from roughly 800 to 1200. However from 1300 or so the climate began to cool. By 1420, we know that the "Little Ice Age" had reached intense levels in Greenland. Excavations of midden or garbage heaps from the Viking farms in both Greenland and Iceland show the shift from the bones of cows and pigs to those of sheep and goats. As the winters lengthened, and the springs and summers shortened, there must have been less and less time for Greenlanders to grow hay. By the mid-fourteenth century deposits from a chieftain’s farm showed a large number of cattle and caribou remains, whereas, a poorer farm only several kilometers away had no trace of domestic animal remains, only seal. Bone samples from Greenland Norse cemeteries confirm that the typical Greenlander diet had increased by this time from 20% sea animals to 80%.

Although Greenland seems to have been uninhabited at the time of initial Norse settlement, after a couple of centuries the Norse in Greenland had to deal with the Inuit. The Thule-Inuit were the successors of the Dorset who migrated south and finally came into contact with the Norse in the 12th century. There are limited sources showing the two cultures interacting; however, scholars know that the Norse referred to the Inuit (and Vinland natives) as skraeling. The Icelandic Annals are among the few existing sources that confirm contact between the Norse and the Inuit. They report an instance of hostility initiated by the Inuit against the Norse, leaving eighteen Greenlanders dead and two boys carried into slavery.

Archeological evidence seems to show that the Inuit traded with the Norse. On the other hand, the evidence shows many Norse artifacts at Inuit sites throughout Greenland and on the Canadian Arctic islands but very few Inuit artifacts in the Norse settlements. This may indicate either European indifference—an instance of cultural resistance to Inuit crafts among them—or perhaps hostile raiding by the Inuit. It is also quite possible that the Norse were trading for perishable items such as meat and furs and had little interest in other Inuit items, much as later Europeans who traded with Native Americans.

We know that the Norse never learned the Inuit techniques of kayak navigation or ring seal hunting. Indeed, they never learned to adjust to the cold winters as the Inuit did. Archeological evidence plainly establishes that by 1300 or so the Inuit had successfully expanded their winter settlements as close to the Europeans as the outer fjords of the Western Settlement. Yet by 1350, the Norse, for whatever reasons, had completely deserted their Western Settlement. It may also have to do with the Inuit being a hunting society, hunted the Norse livestock, forcing the Norse into conflict or abandonment.

In mild weather conditions, a ship could make the 900-mile (1400 kilometers) trip from Iceland to Eastern Settlement within a couple of weeks. Greenlanders had to keep in contact with Iceland and Norway in order to trade. Little is known about any distinctive shipbuilding techniques among the Greenlanders. We do know that they lacked the timber resources of Europe or America, however. So they were completely dependent on Icelandic merchants or, possibly, logging expeditions to the Canadian coast.

The sagas mention Icelanders traveling to Greenland to trade. But the settlement chieftains and large farm owners controlled this trade. The chieftains would trade with the foreign ships and then disperse the goods by trading with the surrounding farmers. The Greenlanders' main commodity was the walrus tusk, which was used primarily in Europe as a substitute for elephant ivory for art décor, whose trade had been blocked by conflict with the Islamic world. Professor Gudmundsson also suggests a very valuable narwhal tusk trade, through a smuggling route via western Iceland (where the Greenlanders came from) to the Orkney islands (where Western Icelanders came from).

Many scholars believe that the royal Norwegian monopoly on shipping contributed to the end of trade and contact. However, Christianity and European customs continued to hold sway among the Greenlanders for the greater part of the fourteenth and fifteenth centuries. In 1921, a Danish historian, Paul Norland, found human remains from the Eastern Settlement in the Herjolfsnes church courtyard. The bodies were dressed in fifteenth century medieval clothing with no indications of malnutrition or genetic deterioration. Most had crucifixes around their necks with their arms crossed as in a stance of prayer. Perhaps the buried were sailors having died en route or while over wintering. It is known from Roman papal records that the Greenlanders were excused from paying their tithes in 1345 because the colony was suffering from poverty. The last reported ship to reach Greenland was a private ship that was "blown off course", reaching Greenland in 1406, and departing in 1410 with the last news of Greenland: the burning at the stake of a condemned witch, the insanity and death of the woman this witch was accused of attempting to seduce through witchcraft, and the marriage of the ship's captain, Thorsteinn Ólafsson, to another Icelander, Sigridur Björnsdóttir. However, there are some suggestions of much later unreported voyages from Europe to Greenland, possibly as late as the 1480s.

The last of the five factors points to the failure of the Norse to adapt to the changing conditions of Greenland. We know that some of the Norse left Greenland in search of a place called Vinland. When hostile natives injured several of them, they returned to Greenland after only 10 years. The Greenland colony survived for some 450-500 years (AD 985 to 1450-1500). The Norse struggled to adapt, as the excavations show plainly. Some of the Norse, perhaps most, dramatically changed their folkways. But it is not known whether they adapted the ways of the Inuit, even, it seems, when faced with extinction. Most likely no single factor brought about their extinction. What is plain is that the settlement died out once and for all, while contributing 5% to the West Greenlanders' DNA.

One intriguing fact is that we find very few fish remains among their middens. This has led to much speculation and argument. Most archeologists reject any decisive judgment based on this one fact, however, as fish bones decompose more quickly than other remains, and may have been disposed of in a different manner. Isotope analysis of the bones of inhabitants shows that marine food sources in fact supplied more and more of the diet of the Norse Greenlanders, making up between 50% and 80% of their diet by the 1300s.

History of Greenland

From Wikipedia, the free encyclopedia



The history of Greenland, the world's largest island, is the history of life under extreme Arctic conditions: an ice cap covers about 95 percent of the island, largely restricting human activity to the coasts.

The first humans are thought to have arrived around 2500 BC. This group apparently died out and were succeeded by several other groups migrating from continental North America. To Europeans, Greenland was unknown until the 10th century, when Icelandic Vikings settled on the southwestern coast. This part of Greenland was apparently unpopulated at the time when the Vikings arrived; the direct ancestors of the modern Inuit Greenlanders are not thought to have arrived until around AD 1200 from the northwest. The Norse settlements along the southwestern coast eventually disappeared after about 500 years. The Inuit thrived in the icy world of the Little Ice Age and were the only inhabitants of the island for several centuries. Denmark-Norway nonetheless claimed the territory, and, after centuries of no contact between the Norse Greenlanders and their Scandinavian brethren, it was feared that the Greenlanders had lapsed back into paganism; so a missionary expedition was sent out to reinstate Christianity in 1721. However, since none of the lost Norse Greenlanders were found, Denmark-Norway instead proceeded to baptize the local Inuit Greenlanders and develop trading colonies along the coast as part of its aspirations as a colonial power. Colonial privileges were retained, such as trade monopoly.

During World War II, Greenland became effectively detached, socially and economically, from Denmark and became more connected to the United States and Canada. After the war, control was returned to Denmark, and, in 1953, the colonial status was transformed into that of an overseas amt (county). Although Greenland is still a part of the Kingdom of Denmark, it has enjoyed home rule since 1979. In 1985, the island became the only territory to leave the European Union, which it had joined as a part of Denmark in 1973.

Protokol Kyoto

Dari Wikipedia bahasa Indonesia, ensiklopedia bebas



Protokol Kyoto adalah sebuah amandemen terhadap Konvensi Rangka Kerja PBB tentang Perubahan Iklim (UNFCCC), sebuah persetujuan internasional mengenai pemanasan global. Negara-negara yang meratifikasi protokol ini berkomitmen untuk mengurangi emisi/pengeluaran karbon dioksida dan lima gas rumah kaca lainnya, atau bekerja sama dalam perdagangan emisi jika mereka menjaga jumlah atau menambah emisi gas-gas tersebut, yang telah dikaitkan dengan pemanasan global.

Jika sukses diberlakukan, Protokol Kyoto diprediksi akan mengurangi rata-rata cuaca global antara 0,02°C dan 0,28°C pada tahun 2050. (sumber: Nature, Oktober 2003)

Nama resmi persetujuan ini adalah Kyoto Protocol to the United Nations Framework Convention on Climate Change (Protokol Kyoto mengenai Konvensi Rangka Kerja PBB tentang Perubahan Iklim). Ia dinegosiasikan di Kyoto pada Desember 1997, dibuka untuk penanda tanganan pada 16 Maret 1998 dan ditutup pada 15 Maret 1999. Persetujuan ini mulai berlaku pada 16 Februari 2005 setelah ratifikasi resmi yang dilakukan Rusia pada 18 November 2004.

Sudahkah blog mu ke-index oleh paman google dengan kata kunci: Kompetisi website kompas muda-im3

Memang susah untuk mendapat urutan pertama menurut paman google, padahal panitia Kompetisi website kompas muda-im3 mensyaratkan bahwa blog kita harus ke index oleh google dan punya peringkat bagus dengan kata kunci: Kompetisi website kompas muda-im3..

Bagaimana cara blog-mu biar ke-index oleh paman google? Sebenarnya jangan takut blog mu ga ke-index, sebenarnya paman google itu baik kok, setiap blog atau website baru pasti akan ke-index, tinggal tunggu aja dua atau tiga hari saja..

Yang masalah blog mu ga bisa urutan 10 besar itu, karena memang blog kita masih baru, alias masih bayi, nyatanya blog yang saya baru buta saja ada di urutan 74, ah sedih melihatnya..

Paman googel itu sebenarnya ga mau dibilang klo database mereka ga up-to-date, jadi setiap ada blog baru yang sesuai dengan kata kunci yang dicari oleh pengguna, mereka akan meng-indexnya..

Ah, tapi sayang nya, panitia Kompetisi website kompas muda-im3, mensyaratkan blog kita di posisi teratas di google. Tapi ada satu hal yang masih membuat saya bertanya-tanya, Apakah urutan blog kita tersebut menurut paman google Indonesia atau paman google Amerika? Atau dengan kata lain google.co.id atau google.com?