Perubahan iklim ialah bidang kajian yang penting dalam sains. Namun, seperti semua sains lain, ia bukanlah sains yang tepat. Pemahaman terhadap sains iklim sentiasa berubah. Perubahan iklim bukanlah perkara baharu; ia sentiasa berlaku, dan akan terus berlaku. Zaman Ais, iaitu tempoh penurunan suhu global dalam jangka masa panjang, ialah satu contoh bagi perkara ini.

Climatic change is an important field of study in science. However, as with all sciences, it is not an exact science. The understanding of the climatic sciences is always changing. Climate change is not new, there has always been climate change, and there will always be climate change. The period known as the Ice Age, which was a long-term period of reduction in global temperatures is an example of this.

Pemanasan global dan perubahan iklim merujuk kepada peningkatan suhu purata global. Peristiwa semula jadi dan aktiviti manusia dipercayai menyumbang kepada peningkatan suhu purata global – ini merupakan bidang perdebatan yang hangat pada masa ini. Ini disebabkan terutamanya oleh peningkatan kesan rumah hijau, iaitu kenaikan suhu di Bumi apabila gas-gas tertentu di atmosfera memerangkap tenaga, seperti gas Karbon Dioksida (CO2). Tempoh pemanasan terkini ini juga bertepatan dengan Revolusi Perindustrian, yang menyaksikan pengeluaran CO2 akibat manusia pada kadar tertinggi, sehingga ramai, seperti Al Gore, membandingkan kenaikan paras CO2 dengan kenaikan suhu, lalu membuat kesimpulan bahawa peningkatan CO2 di atmosfera Bumi merupakan faktor penentu kepada kenaikan suhu. Hubungan CO2-suhu dianggap punca dominan bagi pemanasan global, namun pandangan ini belum muktamad dan terdapat beberapa isu dengan sampel yang digunakan untuk kesimpulan ini.

Global warming and climate change refer to an increase in average global temperatures. Natural events and human activities are believed to be contributing to the increase in average global temperatures – this is the area of current considerable debate. This is caused primarily by increases in the greenhouse which is the rise in temperature on Earth as certain gases in the atmosphere trap energy gases such as Carbon Dioxide (CO2). This latest warming period has also coincided with the Industrial Revolution, which saw the greatest output of human induced CO2, leading many, like Al Gore, to compare the rise in CO2 levels with the rise in temperatures, drawing a conclusion that the rise in CO2 in the earth’s atmosphere was the determining factor in the rise in temperatures. The CO2-temperature connection is considered the dominant cause for global warming, however this view is not conclusive and there is a number of issues with the samples used for this conclusion.

Setiap beberapa tahun, saintis iklim terkemuka dalam Panel Antara Kerajaan mengenai Perubahan Iklim (IPCC) di bawah PBB telah mengeluarkan laporan utama yang memperincikan kemajuan dalam memahami perubahan iklim. Sejak awal lagi, mereka telah mengesyorkan supaya pengurangan pelepasan dilakukan. Badan ini terdiri daripada ratusan saintis iklim dari seluruh dunia. Pada awal Januari 2007, laporan utama keempat IPCC merumuskan bahawa mereka lebih yakin berbanding sebelum ini mengenai perubahan iklim yang disebabkan manusia, kerana pemahaman saintifik yang lebih baik; ‘Pemahaman mengenai pengaruh pemanasan dan penyejukan antropogenik terhadap iklim telah bertambah baik sejak Laporan Penilaian Ketiga (TAR), yang membawa kepada tahap keyakinan yang sangat tinggi bahawa kesan bersih purata global aktiviti manusia sejak 1750 ialah pemanasan.’ Takrifan mereka bagi “keyakinan yang sangat tinggi” dan “sangat berkemungkinan” ialah kebarangkalian 90% untuk betul (laporan 2001 mereka mendakwa tahap kepastian 66%).

Every few years, leading climate scientists at the UN’s Intergovernmental Panel on Climate Change (IPCC) have released major reports detailing the progress in understanding climate change. From the outset they have recommended that there be emission reductions. This body is comprised of hundreds of climate scientists from around the world. At the beginning of January 2007, the IPCC’s fourth major report summarised that they were even more certain than before of human-induced climate change because of better scientific understanding; ‘The understanding of anthropogenic warming and cooling influences on climate has improved since the Third Assessment Report (TAR), leading to very high confidence that the globally averaged net effect of human activities since 1750 has been one of warming.’ Their definition of “very high confidence” and “very likely” is a 90% chance of being correct (their 2001 report claimed a 66% certainty).

Dari segi pelepasan sejarah, negara-negara perindustrian menyumbang kira-kira 80% daripada pengumpulan karbon dioksida di atmosfera setakat ini. Sejak 1950, Amerika Syarikat telah mengeluarkan jumlah terkumpul kira-kira 50.7 bilion tan karbon, manakala China (yang penduduknya 4.6 kali ganda lebih ramai)

In terms of historical emissions, industrialised countries account for around 80% of the carbon dioxide build-up in the atmosphere to date. Since 1950, the US has emitted a cumulative total of roughly 50.7 billion tons of carbon, while China (4.6 times more populous)

dan India (3.5 kali lebih ramai penduduknya) hanya mengeluarkan masing-masing 15.7 dan 4.2 bilion tan. Setiap tahun, lebih daripada 60% pelepasan karbon dioksida perindustrian global berpunca daripada negara-negara perindustrian, di mana hanya kira-kira 20% penduduk dunia tinggal.

and India (3.5 times more populous) have emitted only 15.7 and 4.2 billion tons respectively. Annually, more than 60% of global industrial carbon dioxide emissions originate in industrialized countries, where only about 20% of the world’s population resides.

Sebahagian besar pertumbuhan pelepasan karbon di dunia maju berpunca daripada perindustrian yang pesat sejak era Revolusi Industri. Amerika Syarikat, dengan ekonominya bernilai $14 trilion, ialah pencemar terbesar di dunia dan telah menjadi halangan kepada sebarang perjanjian mengenai sasaran pengurangan pelepasan. Mengurangkan pelepasan bermakna industri di Barat perlu mengeluarkan lebih sedikit, dan ini akan menyebabkan ekonomi Barat mengecut dan bukannya berkembang. Mengurangkan penggunaan dianggap sebagai 'Shirk' dalam Kapitalisme. Sejajar dengan itu, kadar penggunaan bahan api fosil di negara-negara maju juga amat tinggi jika dibandingkan dengan negara-negara lain di dunia. Kehabisan sumber yang tidak boleh diperbaharui dan kemusnahan alam sekitar terutamanya disebabkan oleh corak penggunaan Amerika Syarikat. Penggunaan bahan api fosil di Amerika Syarikat melebihi lima kali ganda purata global.

Much of the growth in emissions in the developed world stem from rapid industrialisation from the industrial revolution era. The US with its $14 trillion economy is the world’s largest polluter and has acted as an obstacle to any agreement on emission reduction targets. Reducing emissions would mean industry in the West would need to produce less – this would lead to economies in the West shrinking rather than growing. To reduce consumption is considered ‘Shirk’ in Capitalism. By the same token, the rate of consumption of fossil fuels in developed countries is also extremely high relative to the rest of the world. The depletion of nonrenewable resources and environmental destruction is primarily caused by the consumption patterns of the US. US consumption of fossil fuels is well over five times the global average.