Kata-kata mutiara

Temen2, ni aku punya kata2 mutiara untuk memotivasi hidup kita agar lebih baik.
ohya, aku berpesan agsr
1. Hormati yang lebih tua
2. Cinai sesama.
3. Sayangi ng lebih muda

SELAPUT MUTIARA

KETIKA SATU PINTU KEBAHAGIAAN TERTUTUP, PINTU YANG LAIN DIBUKAKAN.
TETAPI SERING KALI KITA TERPAKU TERLALU LAMA PADA PINTU YANG TERTUTUP SEHINGGA TIDAK MELIHAT PINTU LAIN YANG DIBUKAKAN BAGI KITA.
DALAM HIDUP,TERKADANG KITA LEBIH BANYAK MENDAPATKAN APA YANG TIDAK KITA INGINKAN. DAN KETIKA KITA MENDAPATKAN APA YANG KITA INGINKAN, AKHIRNYA KITA TAHU BAHWA YANG KITA INGINKAN TERKADANG TIDAK DAPAT MEMBUAT HIDUP KITA MENJADI LEBIH BAHAGIA
BERMIMPILAH TENTANG APA YANG INGIN KAMU IMPIKAN, PERGILAH KE TEMPAT-TEMPAT KAMU INGIN PERGI.
JADILAH SEPERTI YANG KAMU INGINKAN, KERNA KAMU HANYA MEMILIKI SATU KEHIDUPAN DAN SATU KESEMPATAN UNTUK MELAKUKAN HAL-HAL YANG INGIN KAMU LAKUKAN.
MASA DEPAN YANG CERAH BERDASARKAN PADA MASA LALU YANG TELAH DILUPAKAN. KAMU TIDAK DAPAT MELANGKAH DENGAN BAIK DALAM KEHIDUPAN KAMU SAMPAI KAMU MELUPAKAN KEGAGALAN KAMU DAN RASA SAKIT HATI.
WAKTU KAMU LAHIR, KAMU MENANGIS DAN ORANG-ORANG DI SEKELILINGMU TERSENYUM.
JALANILAH HIDUPMU SEHINGGA PADA WAKTU KAMU MENINGGAL, KAMU TERSENYUM DAN ORANG-ORANG DI SEKELILINGMU MENANGIS.
SEMOGA KAMU MENDAPAT CUKUP KEBAHAGIAAN UNTUK MEMBUAT KAMU BAHAGIA, CUKUP
CUBAAN UNTUK MEMBUAT KAMU KUAT, CUKUP PENDERITAAN UNTUK MEMBUAT KAMU MENJADI
MANUSIA YANG SESUNGGUHNYA, DAN CUKUP HARAPAN UNTUK MEMBUAT KAMU POSITIF TERHADAP KEHIDUPAN.
YANG MEMIMPIN WANITA BUKAN AKALNYA, MELAINKAN HATINYA.
HARI INI BILA IA DATANG, JANGAN BIARKAN IA BERLALU PERGI. ESOK KALAU IA MASIH BERTANDANG, JANGAN HARAP IA AKAN DATANG KEMBALI
SESUATU YANG BAIK, BELUM TENTU BENAR.
SESUATU YANG BENAR, BELUM TENTU BAIK.
SESUATU YANG BAGUS, BELUM TENTU BERHARGA.
SESUATU YANG BERHARGA/BERGUNA, BELUM TENTU BAGUS.
AGAMA MENJADI SENDI HIDUP, PENGARUH MENJADI PENJAGANYA. KALAU TIDAK BERSENDI, RUNTUHLAH HIDUP DAN KALAU TIDAK BERPENJAGA, BINASALAH HAYAT. ORANG YANG TERHORMAT ITU KEHORMATANNYA SENDIRI MELARANGNYA BERBUAT JAHAT. -PEPATAH ARAB
JANGAN TERTARIK KEPADA SESEORANG KERNA PARASNYA, SEBAB KEELOKAN PARAS DAPAT MENYESATKAN. JANGAN PULA TERTARIK KEPADA KEKAYAANNYA KERNA KEKAYAAN DAPAT MUSNAH. TERTARIKLAH KEPADA SESEORANG YANG DAPAT MEMBUATMU TERSENYUM, KERNA HANYA SENYUM YANG DAPAT MEMBUAT HARI-HARI YANG GELAP MENJADI CERAH.
SUNGGUH BENAR BAHWA KITA TIDAK TAHU APA YANG KITA MILIKI SAMPAI KITA KEHILANGANNYA,
TETAPI SUNGGUH BENAR PULA BAHWA KITA TIDAK TAHU APA YANG BELUM PERNAH KITA MILIKI SAMPAI KITA MENDAPATKANNYA.
MASA DEPAN YANG CERAH SELALU TERGANTUNG PADA MASA LALU YANG DILUPAKAN.
KITA TIDAK DAPAT MENERUSKAN HIDUP DENGAN BAIK JIKA TIDAK DAPAT MELUPAKAN KEGAGALAN DAN SAKIT HATI DI MASA LALU.
TENTANG WAKTU
AMBILLAH WAKTU UNTUK BERFIKIR, ITU ADALAH SUMBER KEKUATAN.
AMBILLAH WAKTU UNTUK BERMAIN, ITU ADALAH RAHASIA DARI MASA MUDA YANG ABADI.
AMBILLAH WAKTU UNTUK BERDOA, ITU ADALAH SUMBER KETENANGAN.
AMBILLAH WAKTU UNTUK BELAJAR, ITU ADALAH SUMBER KEBIJAKSANAAN.
AMBILLAH WAKTU UNTUK MENCINTAI DAN DICINTAI, ITU ADALAH HAK ISTIMEWA YANG DIBERIKAN TUHAN.
AMBILLAH WAKTU UNTUK BERSAHABAT, ITU ADALAH JALAN MENUJU KEBAHAGIAAN.
AMBILLAH WAKTU UNTUK TERTAWA, ITU ADALAH MUSIK YANG MENGGETARKAN HATI.
AMBILLAH WAKTU UNTUK MEMBERI, ITU ADALAH MEMBUAT HIDUP TERASA BERERTI.
AMBILLAH WAKTU UNTUK BEKERJA, ITU ADALAH NILAI KEBERHASILAN.
AMBILLAH WAKTU UNTUK BERAMAL, ITU ADALAH KUNCI MENUJU SYURGA.
HARTA YANG PALING MENGUNTUNGKAN IALAH SABAR. TEMAN YANG PALING AKRAB ADALAH AMAL. PENGAWAL PERIBADI YANG PALING WASPADA DIAM. BAHASA YANG PALING MANIS SENYUM. DAN IBADAH YANG PALING INDAH TENTUNYA KHUSYUK.
WANITA YANG CANTIK TANPA PERIBADI YANG MULIA ,UMPAMA KACA MATA YANG BERSINAR-BERSINAR, TETAPI TIDAK MELIHAT APA-APA
JANGAN SEKALI-KALI KITA MEREMEHKAN SESUATU PERBUATAN BAIK WALAUPUN HANYA SEKADAR SENYUMAN.
ANDA BUKAN APA YANG ANDA FIKIRKAN TENTANG ANDA, TETAPI APA YANG ANDA FIKIRKAN ITULAH ANDA
HIDUP TAK SELALUNYA INDAH TAPI YANG INDAH ITU TETAP HIDUP DALAM KENANGAN.
HIDUP MEMERLUKAN PENGORBANANAN. PENGORBANAN MEMERLUKAN PERJUANGAN. PERJUANGAN MEMERLUKAN KETABAHAN.
KETABAHAN MEMERLUKAN KEYAKINAN. KEYAKINAN PULA MENENTUKAN KEJAYAAN. KEJAYAAN PULA AKAN MENENTUKAN KEBAHAGIAAN.
KEKAYAAN BUKANLAH SATU DOSA DAN KECANTIKAN BUKANLAH SATU KESALAHAN.
OLEH ITU JIKA ANDA MEMILIKI KEDUA-DUANYA JANGANLAH ANDA LUPA PADA YANG MAHA BERKUASA.
SAMPAN TIDAK AKAN DAPAT BELAYAR DI PADANG PASIR BETAPA PUN JUA EMPUKNYA PASIR ITU -PEPATAH ARAB
PERJALANAN SERIBU BATU BERMULA DARI SATU LANGKAH.
- LAO TZE
KALAULAH ANDA TIDAK MAMPU UNTUK MENGGEMBIRAKAN ORANG LAIN, JANGANLAH PULA ANDA MENAMBAH DUKANYA.
GANTUNGKAN AZAM DAN SEMANGATMU SETINGGI BINTANG DI LANGIT DAN RENDAHKAN HATIMU SERENDAH MUTIARA DI LAUTAN
SAYA PERCAYA, ESOK SUDAH TIDAK BOLEH MENGUBAH APA YANG BERLAKU HARI INI, TETAPI HARI INI MASIH BOLEH MENGUBAH APA YANG AKAN TERJADI PADA HARI ESOK.



KATA ORANG BIJAK


ANDA AKAN LEBIH BANYAK BELAJAR DARI TINDAKAN DARIPADA PERENUNGAN SEMATA.
MARK G. NOLAN, INSTANT CASH FLOW.

CERITAKAN MIMPI DAN TUJUAN HIDUP ANDA PADA ORANG-ORANG YANG MEMILIKI PANDANGAN POSITIF YANG BISA MENGANGKAT ANDA UNTUK BERSAMA-SAMA MAJU KE JENJANG SUKSES YANG LEBIH TINGGI.
MARK G. NOLAN, INSTANT CASH FLOW.

UNTUK MERAIH SUKSES, BERGAULLAH DENGAN ORANG-ORANG SUKSES.
NAPOLEON HILL.

ORANG-ORANG YANG PALING PENTING UNTUK DITEMUI ADALAH MEREKA YANG BERGERAK DI BIDANG BISNIS DAN TOKOH-TOKOH DUNIA, KARENA MEREKA BERBICARA DARI APA YANG MEREKA LIHAT, JALANI DAN KETAHUI, BUKAN DARI APA YANG MEREKA PIKIR SEHARUSNYA TERJADI.
WILLIAM HAZLITT.

KURANG TJERDAS DAPAT DIPERBAIKI DENGAN BELADJAR, KURANG TJAKAP DAPAT DIHILANGKAN DENGAN PENGALAMAN, TETAPI KURANG DJUJUR PAJAH MEMBETULINJA.
[BUNG HATTA]”.(HAL 57)
“KATA2 YANG KELUAR DARI HATI, AKAN MASUK PULA KE DALAM HATI. TETAPI KATA-KATA YANG CUMA KELUAR DARI LIDAH, TIDAKLAH AKAN SAMPAI KE HATI. HANJALAH SEHINGGA KULIT TELINGA.
[AMIR BIN ABDUL KAIS]” (HAL 78)

KAMUT-KAMUT

"Berhati-hatilah ketika mengeluarkan kata-kata, mungkin buat kita itu hanya sebuah gurauan belaka, tapi tidak kepada yang mendengarnya.
"Teman Sejati Adalah Seseorang Yang Menggapai Tanganmu Dan Menyentuh Hatimu Dengan Ketulusan. Ia Selalu Ada Di Saat Kamu Membutuhkan
"Jangan tertarik kepada seseorang karena parasnya,
sebab keelokan paras dapat menyesatkan.
Jangan pula tertarik kepada kekayaannya,
karena kekayaan dapat musnah.
Tertariklah kepada seseorang yang dapat membuatmu tersenyum,
karena hanya senyum yang dapat membuat hari-hari yang gelap menjadi cerah .
Semoga kamu menemukan orang seperti itu.
"Cinta bukan mengajar kita lemah, tetapi membangkitkan kekuatan. Cinta bukan mengajar menghinakan diri, tetapi menghembuskan kegagahan. Cinta bukan melemahkan semangat, tetapi membangkitkan semangat.
"Orang yg berbudi tinggal di belakang layar
tapi sebenarnya ia ada ditempat yang paling depan
kebenaran adalah sederhana
kebenaran tidak memerlukan tipu muslihat untuk meyakinkan
tidak setiap kesalahan adalah kebodohan
pembohong yang terbesar ialah orang yang paling banyak bicara tentang dirinya sendiri
harta terutama manusia adalah kesehatan
lebih baik menghadapi orang yang marah daripada orang yg lapar
seseorang yg kikir selalu merasa kekurangan
kesabaran adalah obat terbaik dalam segala kesulitan
manusia memang tidak mengetahui semua hal, tapi setiap orang harus tahu apa yg patut dimengertinya
orang bisa menjadi lebih kuat dengan makan dan menjadi lebih bijaksana dengan membaca.
"Sesiapa yang tidak pernah merasai kepahitan tidak akan mengenal kemanisan
"Ingatlah, sabar itu iman, uang bukan kawan, dunia hanya pinjaman dan mati tak berteman
"Dalam kepala kaum wanita ada kekurangan, tetapi dalam hati mereka ada kelebihan
"Harta yang paling menguntungkan ialah SABAR.
Teman yang paling akrab adalah AMAL.
Pengawal peribadi yang paling waspada adalah DIAM.
Bahasa yang paling manis adalah SENYUM.
"Dengarkan lah apa yg dikatakan musuhmu.....
biasanya mereka mengatakan hal2 negatif tentang dirimu dengan jujur....
"Hati-hati pada sahabatmu....
biasanya mereka tak mengatakan dengan jujur apa kekurangan & hal negatif dalam dirimu...
Kemenangan yang sesungguh nya adalah hidup lebih baik dari kemarin dan rencanakan sesuatu yang lebih baik dari hari ini untuk esok hari...

Jangan menangis karena gagal dalam cinta,
karena manusia akan meninggalkan semua yg dicintainya....
Orang tak akan pernah merasakan nikmatnya rasa bahagia
bila dia belum pernah mengalami derita.....
Ketika matahari mulai tenggelam,
ada sesuatu dari diri kita yang hilang...
yaitu umur kita semakin tua..
Sukses tidak diukur dari posisi yang dicapai seseorang dalam hidup, tapi dari kesulitan-kesulitan yang berhasil diatasi ketika berusaha meraih sukses
Cintailah orang yang kau cintai sekedarnya saja....
siapa tahu pada suatu hari kelak
ia akan berbalik menjadi orang yang kau benci....
dan bencilah orang yang kau benci sekedarnya saja....
siapa tahu pada suatu hari kelak
ia akan menjadi orang yang kau cintai
"Yang hanya dapat membebaskan kita adalah Kebenaran. Jika kita tidak memahami itu kita senantiasa merasa cemas."
Sahabat adalah dorongan ketika engkau hampir berhenti, petunjuk jalan ketika engkau tersesat, membiaskan senyuman sabar ketika engkau berduka, memapahmu saat engkau hampir tergelincir dan mengalungkan butir-butir mutiara doa pada dadamu...Ikhwan and akhwat...
"Orang mulia menyalahkan dirinya, orang bodoh menyalahkan orang lain"
Mengenal diri yang paling penting, adalah utama demi kesadaran jagat raya.
Berarti pula memahami kesalahan, serta kekeliruannya masing-masing
Jika kejahatan di balas kejahatan, maka itu adalah dendam. Jika kebaikan dibalas kebaikan itu adalah perkara biasa. Jika kebaikan dibalas kejahatan, itu adalah zalim. Tapi jika kejahatan dibalas kebaikan, itu adalah mulia dan terpuji.
Perasaan cinta itu dimulai dari mata, sedangkan rasa suka dimulai dari telinga. Jadi jika kamu mau berhenti menyukai seseorang, cukup dengan menutup telinga. Tapi apabila kamu coba menutup matamu dari orang yang kamu cintai, cinta itu berubah menjadi titisan air mata dan terus tinggal dihatimu dalam jarak waktu yang cukup lama.
Jangan kerana cinta, kita gugur dari perjuangan, dan jangan kerana cinta juga, prinsip kita menjadi larut dan cair. Cinta tidak semestinya akan berakhir dengan perkahwinan dan perkahwinan juga tidak semestinya akan menoktahkan titik akhir kepada percintaan. Kesetiaan akan mengikat cinta, kecurangan akan meranapkan segala kemanisan cinta. Sesebuah perkahwinan akan menjadi indah jika cinta terus bersama.
Cinta sejati ialah kasih Tuhan kepada hambaNya. Kasih murni ialah kasih ibu bapa kepada anaknya. Kasih saudara masa berada. Kasih sahabat masa binasa. Kasih suami isteri sepenanggungan. Kasih orang menaruh harapan.
Yang termanis daripada yang manis di dunia ini ialah pujian kekasih yang terlontar daripada rasa cintanya
Hati-hati dengan cinta, kerana cinta juga dapat membuat orang sehat menjadi sakit, orang gemuk menjadi kurus, orang normal menjadi gila, orang kaya menjadi miskin, raja menjadi budak, jika cintanya itu disambut oleh para pecinta palsu.
hati hati mempermainkan cinta, cinta bisa buat orang luka dan tersiksa bahkan menderita...

Waktu kamu lahir, kamu menangis dan orang-orang di sekelilingmu tersenyum.
Jalanilah hidupmu sehingga pada waktu kamu meninggal, kamu tersenyum dan orang-orang di sekelilingmu menangis.
Jangan suka pamer.
Jadilah jagung, jangan jadi jambu monyet.
Jagung membungkus bijinya yang banyak,
sedangkan jambu monyet memamerkan bijinya yang cuma satu2nya.
Jadilah seperti durian, jangan seperti kedondong.
Durian walaupun diluarnya penuh kulit yang tajam, tetapi dalamnya lembut dan manis.
Beda dengan kedondong, di luarnya mulus dan mengkilat,
tapi didalamnya ada biji yang berduri.
lebih baik memberi dari pada menerima......
lebih baik tangan diatas dari pada tangan dibawah.....
"Awali cintamu dengan kemantapan agar berjalan dengan menyenangkan
"Tak selamanya kekayaan itu membawa kebahagiaan
"Pertolongan yang tulus tidak akan mengharapkan imbalan kembali
"Keramahan adalah senjata penakluk yang paling jujur
"Cinta itu indah tapi tak selamanya keindahan mengandung cinta
"Yang penting bukan berapa lama kita hidup tetapi bagaimana kita hidup
"Waktu yang hilang tak akan dapat diketemukan kembali
"LOST TIME IS NEVER FOUND"
PUISI
hari telah kusam
merangkai bangkai awan
kian masam

bergelut aroma suara tak bergelombang
melangsuti semua sesap nyawa
rengkuh jiwa yang lenguh

Kata-kata yang ia gunakan juga mengandung makna yang dalam, coba saja renungi potongan kalimat berikut: “Pandangan jang baik atas hidup menimbulkan akal, membuka ilham dan membuka djalan bagi memperbarui hidup. (hal 59)”Ia juga pandai mendefinisikan arti sikap sebenarnya, seperti : “Pribadi jang berani, yaitu jang sanggup menghadapi segala kesulitan atau bahaja, dengan tidak kehilangan akal”.

KATA-KATA BIJAKSANA

Demi Allah yang jiwaku berada di tangan-Nya, seseorang tidak beriman hingga ia mencintai saudaranya sebagaimana ia mencintai dirinya sendiri.
Nabi Muhammad SAW

Jauhilah dengki, karena dengki memakan amal kebaikan sebagaimana api memakan kayu bakar.
Nabi Muhammad SAW
Yang terbaik di antara kalian adalah mereka yang berakhlak paling mulia.
Nabi Muhammad SAW
Allah tidak melihat bentuk rupa dan harta benda kalian, tapi Dia melihat hati dan amal kalian.
Nabi Muhammad SAW
Kecintaan kepada Allah melingkupi hati, kecintaan ini membimbing hati dan bahkan merambah ke segala hal.
Imam Al Ghazali
Raihlah ilmu, dan untuk meraih ilmu belajarlah untuk tenang dan sabar.
Khalifah 'Umar
Setiap orang di dunia ini adalah seorang tamu, dan uangnya adalah pinjaman. Tamu itu pastilah akan pergi, cepat atau lambat, dan pinjaman itu haruslah dikembalikan.
Ibnu Mas'ud
Ketahuilah bahwa sabar, jika dipandang dalam permasalahan seseorang adalah ibarat kepala dari suatu tubuh. Jika kepalanya hilang maka keseluruhan tubuh itu akan membusuk. Sama halnya, jika kesabaran hilang, maka seluruh permasalahan akan rusak.
Khalifah 'Ali
Sabar memiliki dua sisi, sisi yang satu adalah sabar, sisi yang lain adalah bersyukur kepada Allah.
Ibnu Mas'ud
Takutlah kamu akan perbuatan dosa di saat sendirian, di saat inilah saksimu adalah juga hakimmu.
Khalifah 'Ali
Orang yang paling aku sukai adalah dia yang menunjukkan kesalahanku.
Khalifah 'Umar
Niat adalah ukuran dalam menilai benarnya suatu perbuatan, oleh karenanya, ketika niatnya benar, maka perbuatan itu benar, dan jika niatnya buruk, maka perbuatan itu buruk.
Imam An Nawawi
Aku mengamati semua sahabat, dan tidak menemukan sahabat yang lebih baik daripada menjaga lidah. Saya memikirkan tentang semua pakaian, tetapi tidak menemukan pakaian yang lebih baik daripada takwa. Aku merenungkan tentang segala jenis amal baik, namun tidak mendapatkan yang lebih baik daripada memberi nasihat baik. Aku mencari segala bentuk rezki, tapi tidak menemukan rezki yang lebih baik daripada sabar.
Khalifah 'Umar
Dia yang menciptakan mata nyamuk adalah Dzat yang menciptakan matahari.
Bediuzzaman Said Nursi
Penderitaan jiwa mengarahkan keburukan. Putus asa adalah sumber kesesatan; dan kegelapan hati, pangkal penderitaan jiwa.
Bediuzzaman Said Nursi
Kebersamaan dalam suatu masyarakat menghasilkan ketenangan dalam segala kegiatan masyarakat itu, sedangkan saling bermusuhan menyebabkan seluruh kegiatan itu mandeg.
Bediuzzaman Said Nursi
Menghidupkan kembali agama berarti menghidupkan suatu bangsa. Hidupnya agama berarti cahaya kehidupan.
Bediuzzaman Said Nursi
Seseorang yang melihat kebaikan dalam berbagai hal berarti memiliki pikiran yang baik. Dan seseoran yang memiliki pikiran yang baik mendapatkan kenikmatan dari hidup.
Bediuzzaman Said Nursi
Pengetahuan tidaklah cukup; kita harus mengamalkannya. Niat tidaklah cukup; kita harus melakukannya.
Johann Wolfgang von Goethe
Pencegahan lebih baik daripada pengobatan.
Johann Wolfgang von Goethe
Kearifan ditemukan hanya dalam kebenaran.
Johann Wolfgang von Goethe
Ilmu pengetahuan tanpa agama adalah pincang.
Einstein
Perdamaian tidak dapat dijaga dengan kekuatan. Hal itu hanya dapat diraih dengan pengertian.
Einstein
Agama sejati adalah hidup yang sesungguhnya; hidup dengan seluruh jiwa seseorang, dengan seluruh kebaikan dan kebajikan seseorang.
Einstein
Dua hal yang membangkitkan ketakjuban saya - langit bertaburkan bintang di atas dan alam semesta yang penuh hikmah di dalamnya.
Einstein
Apa yang saya saksikan di Alam adalah sebuah tatanan agung yang tidak dapat kita pahami dengan sangat tidak menyeluruh, dan hal itu sudah semestinya menjadikan seseorang yang senantiasa berpikir dilingkupi perasaan "rendah hati."
Einstein
Sungguh sedikit mereka yang melihat dengan mata mereka sendiri dan merasakan dengan hati mereka sendiri.
Einstein
Berusahalah untuk tidak menjadi manusia yang berhasil tapi berusahalah menjadi manusia yang berguna.
Einstein
Tidak semua yang dapat menghitung dapat dihitung, dan tidak semua yang dapat dihitung dapat menghitung.
Einstein

Global Warming

Do you know global warming????????????????

For past climate change, see paleoclimatology and geologic temperature record.

Comparison of ground based (blue) and satellite based (red: UAH; green: RSS) records of temperature variations since 1979. Trends plotted since January 1982.

Global mean surface temperature difference from the average for 1961–1990

Mean surface temperature change for the period 1999 to 2008 relative to the average temperatures from 1940 to 1980

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the last century.^[1][A] The Intergovernmental Panel on Climate Change (IPCC) concludes that most of the observed temperature increase since the middle of the 20th century was caused by increasing concentrations of greenhouse gases resulting from human activity such as fossil fuel burning and deforestation.^[1] The IPCC also concludes that variations in natural phenomena such as solar radiation and volcanoes produced most of the warming from pre-industrial times to 1950 and had a small cooling effect afterward.^[2][3] These basic conclusions have been endorsed by more than 40 scientific societies and academies of science,^[B] including all of the national academies of science of the major industrialized countries.^[4]

Climate model projections summarized in the latest IPCC report indicate that the global surface temperature will probably rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century.^[1] The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions. Some other uncertainties include how warming and related changes will vary from region to region around the globe. Most studies focus on the period up to the year 2100. However, warming is expected to continue beyond 2100 even if emissions stop, because of the large heat capacity of the oceans and the long lifetime of carbon dioxide in the atmosphere.^[5][6]

An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts.^[7] The continuing retreat of glaciers, permafrost and sea ice is expected, with warming being strongest in the Arctic. Other likely effects include increases in the intensity of extreme weather events, species extinctions, and changes in agricultural yields.

Political and public debate continues regarding climate change, and what actions (if any) to take in response. The available options are mitigation to reduce further emissions; adaptation to reduce the damage caused by warming; and, more speculatively, geoengineering to reverse global warming. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions.

Temperature changes

Main article: Temperature record

Two millennia of mean surface temperatures according to different reconstructions, each smoothed on a decadal scale. The unsmoothed, annual value for 2004 is also plotted for reference.

The most commonly discussed measure of global warming is the trend in globally averaged temperature near the Earth's surface. Expressed as a linear trend, this temperature rose by 0.74°C ±0.18°C over the period 1906-2005. The rate of warming over the last half of that period was almost double that for the period as a whole (0.13°C ±0.03°C per decade, versus 0.07°C ± 0.02°C per decade). The urban heat island effect is estimated to account for about 0.002 °C of warming per decade since 1900.^[8] Temperatures in the lower troposphere have increased between 0.12 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to satellite temperature measurements. Temperature is believed to have been relatively stable over the one or two thousand years before 1850, with regionally-varying fluctuations such as the Medieval Warm Period or the Little Ice Age.

Based on estimates by NASA's Goddard Institute for Space Studies, 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree.^[9] Estimates prepared by the World Meteorological Organization and the Climatic Research Unit concluded that 2005 was the second warmest year, behind 1998.^[10][11] Temperatures in 1998 were unusually warm because the strongest El Niño in the past century occurred during that year.^[12] Global temperature is subject to short-term fluctuations that overlay long term trends and can temporarily mask them. The relative stability in temperature from 1999 to 2009 is consistent with such an episode.^{[13] [14]}

Temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25 °C per decade against 0.13 °C per decade).^[15] Ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation.^[16] The Northern Hemisphere warms faster than the Southern Hemisphere because it has more land and because it has extensive areas of seasonal snow and sea-ice cover subject to the ice-albedo feedback. Although more greenhouse gases are emitted in the Northern than Southern Hemisphere this does not contribute to the difference in warming because the major greenhouse gases persist long enough to mix between hemispheres.^[17]

The thermal inertia of the oceans and slow responses of other indirect effects mean that climate can take centuries or longer to adjust to changes in forcing. Climate commitment studies indicate that even if greenhouse gases were stabilized at 2000 levels, a further warming of about 0.5 °C (0.9 °F) would still occur.^[18]

Radiative forcing

Main article: Radiative forcing

External forcing is a term used in climate science for processes external to the climate system (though not necessarily external to Earth). Climate responds to several types of external forcing, such as changes in greenhouse gas concentrations, changes in solar luminosity, volcanic eruptions, and variations in Earth's orbit around the Sun.^[2] Attribution of recent climate change focuses on the first three types of forcing. Orbital cycles vary slowly over tens of thousands of years and thus are too gradual to have caused the temperature changes observed in the past century.

Greenhouse gases

Main articles: Greenhouse gas and Greenhouse effect

Greenhouse effect schematic showing energy flows between space, the atmosphere, and earth's surface. Energy exchanges are expressed in watts per square meter (W/m²).

Recent atmospheric carbon dioxide (CO₂) increases. Monthly CO₂ measurements display seasonal oscillations in overall yearly uptrend; each year's maximum occurs during the Northern Hemisphere's late spring, and declines during its growing season as plants remove some atmospheric CO₂.

The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in the atmosphere warm a planet's lower atmosphere and surface. It was discovered by Joseph Fourier in 1824 and was first investigated quantitatively by Svante Arrhenius in 1896.^[19] Existence of the greenhouse effect as such is not disputed, even by those who do not agree that the recent temperature increase is attributable to human activity. The question is instead how the strength of the greenhouse effect changes when human activity increases the concentrations of greenhouse gases in the atmosphere.

Naturally occurring greenhouse gases have a mean warming effect of about 33 °C (59 °F).^[20][C] The major greenhouse gases are water vapor, which causes about 36–70 percent of the greenhouse effect; carbon dioxide (CO₂), which causes 9–26 percent; methane (CH₄), which causes 4–9 percent^{[not in citation given]}; and ozone (O₃), which causes 3–7 percent.^[21][22] Clouds also affect the radiation balance, but they are composed of liquid water or ice and so are considered separately from water vapor and other gases.

Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO₂, methane, tropospheric ozone, CFCs and nitrous oxide. The concentrations of CO₂ and methane have increased by 36% and 148% respectively since the mid-1700s.^[23] These levels are much higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from ice cores.^[24] Less direct geological evidence indicates that CO₂ values this high were last seen about 20 million years ago.^[25] Fossil fuel burning has produced about three-quarters of the increase in CO₂ from human activity over the past 20 years. Most of the rest is due to land-use change, particularly deforestation.^[26]

CO₂ concentrations are continuing to rise due to burning of fossil fuels and land-use change. The future rate of rise will depend on uncertain economic, sociological, technological, and natural developments. Accordingly, the IPCC Special Report on Emissions Scenarios gives a wide range of future CO₂ scenarios, ranging from 541 to 970 ppm by the year 2100.^[27] Fossil fuel reserves are sufficient to reach these levels and continue emissions past 2100 if coal, tar sands or methane clathrates are extensively exploited.^[28]

The destruction of stratospheric ozone by chlorofluorocarbons is sometimes mentioned in relation to global warming. Although there are a few areas of linkage, the relationship between the two is not strong. Reduction of stratospheric ozone has a cooling influence, but substantial ozone depletion did not occur until the late 1970s.^[29] Tropospheric ozone contributes to surface warming.^[30]

Aerosols and soot

Ship tracks over the Atlantic Ocean on the east coast of the United States. The climatic impacts from aerosol forcing could have a large effect on climate through the indirect effect.

Global dimming, a gradual reduction in the amount of global direct irradiance at the Earth's surface, has partially counteracted global warming from 1960 to the present.^[31] The main cause of this dimming is aerosols produced by volcanoes and pollutants. These aerosols exert a cooling effect by increasing the reflection of incoming sunlight. James Hansen and colleagues have proposed that the effects of the products of fossil fuel combustion—CO₂ and aerosols—have largely offset one another in recent decades, so that net warming has been driven mainly by non-CO₂ greenhouse gases.^[32]

In addition to their direct effect by scattering and absorbing solar radiation, aerosols have indirect effects on the radiation budget.^[33] Sulfate aerosols act as cloud condensation nuclei and thus lead to clouds that have more and smaller cloud droplets. These clouds reflect solar radiation more efficiently than clouds with fewer and larger droplets.^[34] This effect also causes droplets to be of more uniform size, which reduces growth of raindrops and makes the cloud more reflective to incoming sunlight.^[35]

Soot may cool or warm, depending on whether it is airborne or deposited. Atmospheric soot aerosols directly absorb solar radiation, which heats the atmosphere and cools the surface. Regionally (but not globally), as much as 50% of surface warming due to greenhouse gases may be masked by atmospheric brown clouds.^[36] When deposited, especially on glaciers or on ice in arctic regions, the lower surface albedo can also directly heat the surface.^[37] The influences of aerosols, including black carbon, are most pronounced in the tropics and sub-tropics, particularly in Asia, while the effects of greenhouse gases are dominant in the extratropics and southern hemisphere.^[38]

Solar variation

Main article: Solar variation

Solar variation over the last thirty years.

Variations in solar output have been the cause of past climate changes.^[39] Although solar forcing is generally thought to be too small to account for a significant part of global warming in recent decades,^[40][41] a few studies disagree, such as a recent phenomenological analysis that indicates the contribution of solar forcing may be underestimated.^[42]

Greenhouse gases and solar forcing affect temperatures in different ways. While both increased solar activity and increased greenhouse gases are expected to warm the troposphere, an increase in solar activity should warm the stratosphere while an increase in greenhouse gases should cool the stratosphere.^[2] Observations show that temperatures in the stratosphere have been steady or cooling since 1979, when satellite measurements became available. Radiosonde (weather balloon) data from the pre-satellite era show cooling since 1958, though there is greater uncertainty in the early radiosonde record.^[43]

A related hypothesis, proposed by Henrik Svensmark, is that magnetic activity of the sun deflects cosmic rays that may influence the generation of cloud condensation nuclei and thereby affect the climate.^[44] Other research has found no relation between warming in recent decades and cosmic rays.^[45][46] A recent study concluded that the influence of cosmic rays on cloud cover is about a factor of 100 lower than needed to explain the observed changes in clouds or to be a significant contributor to present-day climate change.^[47]

Feedback

Main article: Effects of global warming

A positive feedback is a process that amplifies some change. Thus, when a warming trend results in effects that induce further warming, the result is a positive feedback; when the warming results in effects that reduce the original warming, the result is a negative feedback. The main positive feedback in global warming involves the tendency of warming to increase the amount of water vapor in the atmosphere. The main negative feedback in global warming is the effect of temperature on emission of infrared radiation: as the temperature of a body increases, the emitted radiation increases with the fourth power of its absolute temperature.

Water vapor feedback

If the atmosphere is warmed, the saturation vapor pressure increases, and the amount of water vapor in the atmosphere will tend to increase. Since water vapor is a greenhouse gas, the increase in water vapor content makes the atmosphere warm further; this warming causes the atmosphere to hold still more water vapor (a positive feedback), and so on until other processes stop the feedback loop. The result is a much larger greenhouse effect than that due to CO₂ alone. Although this feedback process causes an increase in the absolute moisture content of the air, the relative humidity stays nearly constant or even decreases slightly because the air is warmer.^[48]

Cloud feedback

Warming is expected to change the distribution and type of clouds. Seen from below, clouds emit infrared radiation back to the surface, and so exert a warming effect; seen from above, clouds reflect sunlight and emit infrared radiation to space, and so exert a cooling effect. Whether the net effect is warming or cooling depends on details such as the type and altitude of the cloud. These details were poorly observed before the advent of satellite data and are difficult to represent in climate models.^[48]

Lapse rate

The atmosphere's temperature decreases with height in the troposphere. Since emission of infrared radiation varies with temperature, longwave radiation escaping to space from the relatively cold upper atmosphere is less than that emitted toward the ground from the lower atmosphere. Thus, the strength of the greenhouse effect depends on the atmosphere's rate of temperature decrease with height. Both theory and climate models indicate that global warming will reduce the rate of temperature decrease with height, producing a negative lapse rate feedback that weakens the greenhouse effect. Measurements of the rate of temperature change with height are very sensitive to small errors in observations, making it difficult to establish whether the models agree with observations.^[49]

Ice-albedo feedback

Aerial photograph showing a section of sea ice. The lighter blue areas are melt ponds and the darkest areas are open water, both have a lower albedo than the white sea ice. The melting ice contributes to the ice-albedo feedback.

When ice melts, land or open water takes its place. Both land and open water are on average less reflective than ice and thus absorb more solar radiation. This causes more warming, which in turn causes more melting, and this cycle continues.^[50]

Arctic methane release

Warming is also the triggering variable for the release of methane in the arctic^[51]. Methane released from thawing permafrost such as the frozen peat bogs in Siberia, and from methane clathrate on the sea floor, creates a positive feedback.^[52]

Reduced absorption of CO₂ by the oceanic ecosystems

Ocean ecosystems' ability to sequester carbon is expected to decline as the oceans warm. This is because warming reduces the nutrient levels of the mesopelagic zone (about 200 to 1000 m deep), which limits the growth of diatoms in favor of smaller phytoplankton that are poorer biological pumps of carbon.^[53]

CO₂ release from oceans

cooler water can absorb more CO₂. As ocean temperatures rise some of this CO₂ will be realeased. This is one of the main reasons why atmospheric CO₂ is lower during an ice age. There is a greater mass of CO₂ contained in the oceans than there is in the atmosphere.

Gas release

Release of gases of biological origin may be affected by global warming, but research into such effects is at an early stage. Some of these gases, such as Nitrous oxide released from peat, directly affect climate.^[54] Others, such as Dimethyl sulfide released from oceans, have indirect effects.^[55]

Climate models

Main article: Global climate model

Calculations of global warming prepared in or before 2001 from a range of climate models under the SRES A2 emissions scenario, which assumes no action is taken to reduce emissions and regionally divided economic development.

The geographic distribution of surface warming during the 21^st century calculated by the HadCM3 climate model if a business as usual scenario is assumed for economic growth and greenhouse gas emissions. In this figure, the globally averaged warming corresponds to 3.0 °C (5.4 °F).

The main tools for projecting future climate changes are mathematical models based on physical principles including fluid dynamics, thermodynamics and radiative transfer. Although they attempt to include as many processes as possible, simplifications of the actual climate system are inevitable because of the constraints of available computer power and limitations in knowledge of the climate system. All modern climate models are in fact combinations of models for different parts of the Earth. These include an atmospheric model for air movement, temperature, clouds, and other atmospheric properties; an ocean model that predicts temperature, salt content, and circulation of ocean waters; models for ice cover on land and sea; and a model of heat and moisture transfer from soil and vegetation to the atmosphere. Some models also include treatments of chemical and biological processes.^[56] Warming due to increasing levels of greenhouse gases is not an assumption of the models; rather, it is an end result from the interaction of greenhouse gases with radiative transfer and other physical processes in the models.^[57] Although much of the variation in model outcomes depends on the greenhouse gas emissions used as inputs, the temperature effect of a specific greenhouse gas concentration (climate sensitivity) varies depending on the model used. The representation of clouds is one of the main sources of uncertainty in present-generation models.^[58]

Global climate model projections of future climate most often have used estimates of greenhouse gas emissions from the IPCC Special Report on Emissions Scenarios (SRES). In addition to human-caused emissions, some models also include a simulation of the carbon cycle; this generally shows a positive feedback, though this response is uncertain. Some observational studies also show a positive feedback.^[59][60][61] Including uncertainties in future greenhouse gas concentrations and climate sensitivity, the IPCC anticipates a warming of 1.1 °C to 6.4 °C (2.0 °F to 11.5 °F) by the end of the 21st century, relative to 1980–1999.^[1]

Models are also used to help investigate the causes of recent climate change by comparing the observed changes to those that the models project from various natural and human-derived causes. Although these models do not unambiguously attribute the warming that occurred from approximately 1910 to 1945 to either natural variation or human effects, they do indicate that the warming since 1970 is dominated by man-made greenhouse gas emissions.^[62]

The physical realism of models is tested by examining their ability to simulate current or past climates.^[63] Current climate models produce a good match to observations of global temperature changes over the last century, but do not simulate all aspects of climate.^[26] While a 2007 study by David Douglass and colleagues found that the models did not accurately predict observed changes in the tropical troposphere,^[64] a 2008 paper published by a 17-member team led by Ben Santer noted errors and incorrect assumptions in the Douglass study, and found instead that the models and observations were not statistically different.^[65] Not all effects of global warming are accurately predicted by the climate models used by the IPCC. For example, observed Arctic shrinkage has been faster than that predicted.^[66]

Attributed and expected effects

Environmental

Main articles: Effects of global warming and Regional effects of global warming

Sparse records indicate that glaciers have been retreating since the early 1800s. In the 1950s measurements began that allow the monitoring of glacial mass balance, reported to the WGMS and the NSIDC.

It usually is impossible to connect specific weather events to global warming. Instead, global warming is expected to cause changes in the overall distribution and intensity of events, such as changes to the frequency and intensity of heavy precipitation. Broader effects are expected to include glacial retreat, Arctic shrinkage, and worldwide sea level rise. Some effects on both the natural environment and human life are, at least in part, already being attributed to global warming. A 2001 report by the IPCC suggests that glacier retreat, ice shelf disruption such as that of the Larsen Ice Shelf, sea level rise, changes in rainfall patterns, and increased intensity and frequency of extreme weather events are attributable in part to global warming.^[67] Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.^[68]

Social and economic effects of global warming may be exacerbated by growing population densities in affected areas. Temperate regions are projected to experience some benefits, such as fewer cold-related deaths.^[69] A summary of probable effects and recent understanding can be found in the report made for the IPCC Third Assessment Report by Working Group II.^[67] The newer IPCC Fourth Assessment Report summary reports that there is observational evidence for an increase in intense tropical cyclone activity in the North Atlantic Ocean since about 1970, in correlation with the increase in sea surface temperature (see Atlantic Multidecadal Oscillation), but that the detection of long-term trends is complicated by the quality of records prior to routine satellite observations. The summary also states that there is no clear trend in the annual worldwide number of tropical cyclones.^[1]

Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090-2100 relative to 1980-1999,^[1] new trade routes resulting from arctic shrinkage,^[70] possible thermohaline circulation slowing, increasingly intense (but less frequent) hurricanes and extreme weather events,^[71] reductions in the ozone layer, changes in agriculture yields, changes in the range of climate-dependent disease vectors,^[72] which has been linked to increases in the prevalence of malaria and dengue fever,^[73] and ocean oxygen depletion.^[74] Increased atmospheric CO₂ increases the amount of CO₂ dissolved in the oceans.^[75] CO₂ dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004,^[76] and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO₂.^[1][77] Heat and carbon dioxide trapped in the oceans may still take hundreds years to be re-emitted, even after greenhouse gas emissions are eventually reduced.^[6] Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns and disruptions in food webs.^[78] One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.^[79] However, few mechanistic studies have documented extinctions due to recent climate change,^[80] and one study suggests that projected rates of extinction are uncertain.^[81]

The Tibetan Plateau contains the world's third-largest store of ice. Qin Dahe, the former head of the China Meteorological Administration, said that the recent fast pace of melting and warmer temperatures will be good for agriculture and tourism in the short term; but issued a strong warning:

"Temperatures are rising four times faster than elsewhere in China, and the Tibetan glaciers are retreating at a higher speed than in any other part of the world." "In the short term, this will cause lakes to expand and bring floods and mudflows." "In the long run, the glaciers are vital lifelines for Asian rivers, including the Indus and the Ganges. Once they vanish, water supplies in those regions will be in peril."^[82]

Economic

Main articles: Economics of global warming and Low-carbon economy

Projected temperature increase for a range of stabilization scenarios (the colored bands). The black line in middle of the shaded area indicates 'best estimates'; the red and the blue lines the likely limits. From IPCC AR4.

The IPCC reports the aggregate net economic costs of damages from climate change globally (discounted to the specified year). In 2005, the average social cost of carbon from 100 peer-reviewed estimates is US$12 per tonne of CO₂, but range -$3 to $95/tCO₂. The IPCC's gives these cost estimates with the caveats, "Aggregate estimates of costs mask significant differences in impacts across sectors, regions and populations and very likely underestimate damage costs because they cannot include many non-quantifiable impacts."^[83]

One widely publicized report on potential economic impact is the Stern Review, written by Sir Nicholas Stern. It suggests that extreme weather might reduce global gross domestic product by up to one percent, and that in a worst-case scenario global per capita consumption could fall by the equivalent of 20 percent.^[84] The response to the Stern Review was mixed. The Review's methodology, advocacy and conclusions were criticized by several economists, including Richard Tol, Gary Yohe,^[85] Robert Mendelsohn^[86] and William Nordhaus.^[87] Economists that have generally supported the Review include Terry Barker,^[88] William Cline,^[89] and Frank Ackerman.^[90] According to Barker, the costs of mitigating climate change are 'insignificant' relative to the risks of unmitigated climate change.^[91]

According to United Nations Environment Programme (UNEP), economic sectors likely to face difficulties related to climate change include banks, agriculture, transport and others.^[92] Developing countries dependent upon agriculture will be particularly harmed by global warming.^[93]

Responses to global warming

The broad agreement among climate scientists that global temperatures will continue to increase has led some nations, states, corporations and individuals to implement responses. These responses to global warming can be divided into mitigation of the causes and effects of global warming, adaptation to the changing global environment, and geoengineering to reverse global warming.

Mitigation

Main article: Mitigation of global warming

Carbon capture and storage (CCS) is an approach to mitigation. Emissions may be sequestered from fossil fuel power plants, or removed during processing in hydrogen production. When used on plants, it is known as bio-energy with carbon capture and storage.

Mitigation of global warming is accomplished through reductions in the rate of anthropogenic greenhouse gas release. Models suggest that mitigation can quickly begin to slow global warming, but that temperatures will appreciably decrease only after several centuries.^[94] The world's primary international agreement on reducing greenhouse gas emissions is the Kyoto Protocol, an amendment to the UNFCCC negotiated in 1997. The Protocol now covers more than 160 countries and over 55 percent of global greenhouse gas emissions.^[95] As of June 2009, only the United States, historically the world's largest emitter of greenhouse gases, has refused to ratify the treaty. The treaty expires in 2012. International talks began in May 2007 on a future treaty to succeed the current one.^[96] UN negotiations are now gathering pace in advance of a meeting in Copenhagen in December 2009.^[97]

Many environmental groups encourage individual action against global warming, as well as community and regional actions. Others have suggested a quota on worldwide fossil fuel production, citing a direct link between fossil fuel production and CO₂ emissions.^[98][99]

There has also been business action on climate change, including efforts to improve energy efficiency and limited moves towards use of alternative fuels. In January 2005 the European Union introduced its European Union Emission Trading Scheme, through which companies in conjunction with government agree to cap their emissions or to purchase credits from those below their allowances. Australia announced its Carbon Pollution Reduction Scheme in 2008. United States President Barack Obama has announced plans to introduce an economy-wide cap and trade scheme.^[100]

The IPCC's Working Group III is responsible for crafting reports on mitigation of global warming and the costs and benefits of different approaches. The 2007 IPCC Fourth Assessment Report concludes that no one technology or sector can be completely responsible for mitigating future warming. They find there are key practices and technologies in various sectors, such as energy supply, transportation, industry, and agriculture, that should be implemented to reduced global emissions. They estimate that stabilization of carbon dioxide equivalent between 445 and 710 ppm by 2030 will result in between a 0.6 percent increase and three percent decrease in global gross domestic product.^[101]

Adaptation

Main article: Adaptation to global warming

A wide variety of measures have been suggested for adaptation to global warming. These measures range from the trivial, such as the installation of air-conditioning equipment, to major infrastructure projects, such as abandoning settlements threatened by sea level rise.

Measures including water conservation,^[102] water rationing, adaptive agricultural practices,^[103] construction of flood defences,^[104] Martian colonization,^[105] changes to medical care,^[106] and interventions to protect threatened species^[107] have all been suggested. A wide-ranging study of the possible opportunities for adaptation of infrastructure has been published by the Institute of Mechanical Engineers.^[108]

Geoengineering

Main article: Geoengineering

Geoengineering is the deliberate modification of Earth's natural environment on a large scale to suit human needs.^[109] An example is greenhouse gas remediation, which removes greenhouse gases from the atmosphere, usually through carbon sequestration techniques such as carbon dioxide air capture.^[110] Solar radiation management reduces absorbed solar radiation, such as by the addition of stratospheric sulfur aerosols ^[111] or painting roofs of houses white ^[112]. No large-scale geoengineering projects have yet been undertaken.

Debate and skepticism

Main articles: Global warming controversy and Politics of global warming

See also: Scientific opinion on climate change and Climate change denial

Per capita greenhouse gas emissions in 2000, including land-use change.

Per country greenhouse gas emissions in 2000, including land-use change.

Increased publicity of the scientific findings surrounding global warming has resulted in political and economic debate.^[113] Poor regions, particularly Africa, appear at greatest risk from the projected effects of global warming, while their emissions have been small compared to the developed world.^[114] The exemption of developing countries from Kyoto Protocol restrictions has been used to justify non-ratification by the U.S. and a previous Australian Government.^[115] (Australia has since ratified the Kyoto protocol.^[116]) Another point of contention is the degree to which emerging economies such as India and China should be expected to constrain their emissions.^[117] The U.S. contends that if it must bear the cost of reducing emissions, then China should do the same^[118][119] since China's gross national CO₂ emissions now exceed those of the U.S.^{[120][121][122]} China has contended that it is less obligated to reduce emissions since its per capita responsibility and per capita emissions are less that of the U.S.^[123] India, also exempt, has made similar contentions.^[124]

In 2007-2008 the Gallup Polls surveyed 127 countries. Over a third of the world's population were unaware of global warming, developing countries less aware than developed, and Africa the least aware. Awareness does not equate to belief that global warming is a result of human activities. Of those aware, Latin America leads in belief that temperature changes are a result of human activities while Africa, parts of Asia and the Middle East, and a few countries from the Former Soviet Union lead in the opposite.^[125] In the western world, the concept and the appropriate responses are contested. Nick Pidgeon of Cardiff University finds that "results show the different stages of engagement about global warming on each side of the Atlantic" where Europe debates the appropriate responses while the United States debates whether climate change is happening.^[126]

Debates weigh the benefits of limiting industrial emissions of greenhouse gases against the costs that such changes would entail.^[101] Using economic incentives, alternative and renewable energy have been promoted to reduce emissions while building infrastructure.^[127][128] Business-centered organizations such as the Competitive Enterprise Institute, conservative commentators, and companies such as ExxonMobil have downplayed IPCC climate change scenarios, funded scientists who disagree with the scientific consensus, and provided their own projections of the economic cost of stricter controls.^{[129][130][131][132]} Environmental organizations and public figures have emphasized changes in the current climate and the risks they entail, while promoting adaptation to changes in infrastructural needs and emissions reductions.^[133] Some fossil fuel companies have scaled back their efforts in recent years,^[134] or called for policies to reduce global warming.^[135]

Some global warming skeptics in the science or political community dispute all or some of the global warming scientific consensus, questioning whether global warming is actually occurring, whether human activity has contributed significantly to the warming, and on the magnitude of the threat posed by global warming.

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